Since Illinois became a U.S. state in 1818, it has sent congressional delegations to the United States Senate and United States House of Representatives. Each state elects two senators to serve for six years, and members of the House to two-year terms. Before becoming a state, the Illinois Territory elected a non-voting delegate at-large to Congress from 1812 to 1818.
These are tables of congressional delegations from Illinois to the United States Senate and the United States House of Representatives.
Current delegation
{| class="wikitable floatright" style="text-align: center;"
|-
! colspan=3 | Current U.S. senators from Illinois
|-
! rowspan=2 | <br/><br/>
{| class="wikitable"
! CPVI :
|-
|
|}
! Class II senator
! Class III senator
|- style="vertical-align: top;"
| 149x149px<br/>Dick Durbin<br/><br>
| x150px<br/>Tammy Duckworth<br/><br>
|-
! Party
|
|
|-
! Incumbent since
| January 3, 1997
| January 3, 2017
|}
Illinois's current congressional delegation in the consists of its two senators, both of whom are Democrats, and its 17 representatives: 14 Democrats and 3 Republicans.
The current dean of the Illinois delegation is Senator Dick Durbin, having served in the Senate since 1997 and in Congress since 1983.
United States Senate
{| class="wikitable sticky-header" style="text-align:center"
|- style="height:2em"
! colspan="2" | Class II senator
! Congress
! colspan="2" | Class III senator
|- style="height:2em"
| rowspan=5 | Jesse B. Thomas (DR)
| rowspan="3" style="background: #D3D3D3"|
| 15th (1817–1819)
|style="background: #D3D3D3"|
| rowspan=4 | Ninian Edwards (DR)
|- style="height:2em"
| 16th (1819–1821)
| rowspan="4" |
|- style="height:2em"
| 17th (1821–1823)
|- style="height:1.25em"
| rowspan="4" |
| rowspan=2 | 18th (1823–1825)
|- style="height:2em"
| | John McLean (DR)
|- style="height:2em"
| rowspan=2 | Jesse B. Thomas (NR)
| 19th (1825–1827)
| rowspan="5" style="background: #D3D3D3"|
| rowspan=8 | Elias Kane (J)
|- style="height:2em"
| 20th (1827–1829)
|- style="height:1.25em"
| | John McLean (J)
| rowspan="5" style="background: #D3D3D3"|
| rowspan=3 | 21st (1829–1831)
|- style="height:2em"
| | David J. Baker (J)
|- style="height:1.25em"
| rowspan=5 | John M. Robinson (J)
|- style="height:2em"
| 22nd (1831–1833)
| rowspan="4" |
|- style="height:2em"
| 23rd (1833–1835)
|- style="height:1.25em"
| rowspan="4" |
| rowspan=2 | 24th (1835–1837)
|- style="height:2em"
| | William Lee D. Ewing (J)
|- style="height:2em"
| rowspan=2 | John M. Robinson (D)
| 25th (1837–1839)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | Richard M. Young (D)
|- style="height:2em"
| 26th (1839–1841)
|- style="height:2em"
| rowspan=2 | Samuel McRoberts (D)
| rowspan="4" style="background: #D3D3D3"|
| 27th (1841–1843)
|- style="height:1.25em"
| rowspan=2 | 28th (1843–1845)
| rowspan="4" |
| rowspan=4 | Sidney Breese (D)
|- style="height:1.25em"
| rowspan=2 | James Semple (D)
|- style="height:2em"
| 29th (1845–1847)
|- style="height:2em"
| rowspan=8 | Stephen A. Douglas (D)
| rowspan="3" |
| 30th (1847–1849)
|- style="height:2em"
| 31st (1849–1851)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | James Shields (D)
|- style="height:2em"
| 32nd (1851–1853)
|- style="height:2em"
| rowspan="3" style="background: #D3D3D3"|
| 33rd (1853–1855)
|- style="height:2em"
| 34th (1855–1857)
| rowspan="3" |
| | Lyman Trumbull (D)
|- style="height:2em"
| 35th (1857–1859)
| rowspan="9" |Lyman Trumbull (R)
|- style="height:2em"
| rowspan="5" |
| 36th (1859–1861)
|- style="height:1.25em"
| rowspan=3 | 37th (1861–1863)
| rowspan="5" style="background: #D3D3D3"|
|- style="height:2em"
| | Orville Browning (R)
|- style="height:1.25em"
| rowspan=2 | William A. Richardson (D)
|- style="height:2em"
| 38th (1863–1865)
|- style="height:2em"
| rowspan=3 | Richard Yates (R)
| rowspan="3" style="background: #D3D3D3"|
| 39th (1865–1867)
|- style="height:2em"
| 40th (1867–1869)
| rowspan="3" |
|- style="height:2em"
| 41st (1869–1871)
|- style="height:2em"
| rowspan=3 | John A. Logan (R)
| rowspan="3" |
| 42nd (1871–1873)
| |Lyman Trumbull (LR)
|- style="height:2em"
| 43rd (1873–1875)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | Richard J. Oglesby (R)
|- style="height:2em"
| 44th (1875–1877)
|- style="height:2em"
| rowspan=3 | David Davis (I)
| rowspan="3" style="background: #D3D3D3"|
| 45th (1877–1879)
|- style="height:2em"
| 46th (1879–1881)
| rowspan="3" |
| rowspan=4 | John A. Logan (R)
|- style="height:2em"
| 47th (1881–1883)
|- style="height:2em"
| rowspan=16 | Shelby M. Cullom (R)
| rowspan="4" |
| 48th (1883–1885)
|- style="height:1.25em"
| rowspan=2 | 49th (1885–1887)
| rowspan="4" style="background: #D3D3D3"|
|- style="height:1.25em"
| rowspan=3 | Charles B. Farwell (R)
|- style="height:2em"
| 50th (1887–1889)
|- style="height:2em"
| rowspan="3" style="background: #D3D3D3"|
| 51st (1889–1891)
|- style="height:2em"
| 52nd (1891–1893)
| rowspan="3" |
| rowspan=3 | John M. Palmer (D)
|- style="height:2em"
| 53rd (1893–1895)
|- style="height:2em"
| rowspan="3" |
| 54th (1895–1897)
|- style="height:2em"
| 55th (1897–1899)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | William E. Mason (R)
|- style="height:2em"
| 56th (1899–1901)
|- style="height:2em"
| rowspan="3" style="background: #D3D3D3"|
| 57th (1901–1903)
|- style="height:2em"
| 58th (1903–1905)
| rowspan="3" |
| rowspan=3 | Albert J. Hopkins (R)
|- style="height:2em"
| 59th (1905–1907)
|- style="height:2em"
| rowspan="3" |
| 60th (1907–1909)
|- style="height:2em"
| 61st (1909–1911)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=2 | William Lorimer (R)
|- style="height:2em"
| 62nd (1911–1913)
|- style="height:2em"
| rowspan=3 | J. Hamilton Lewis (D)
| rowspan="3" style="background: #D3D3D3"|
| 63rd (1913–1915)
| rowspan=4 | Lawrence Y.<br/>Sherman (R)
|- style="height:2em"
| 64th (1915–1917)
| rowspan="3" |
|- style="height:2em"
| 65th (1917–1919)
|- style="height:2em"
| rowspan=3 | Medill McCormick (R)
| rowspan="4" |
| 66th (1919–1921)
|- style="height:2em"
| 67th (1921–1923)
| rowspan="5" style="background: #D3D3D3"|
| rowspan=4 | William B. McKinley (R)
|- style="height:1.25em"
| rowspan=2 | 68th (1923–1925)
|- style="height:1.25em"
| rowspan=6 | Charles S. Deneen (R)
|- style="height:1.25em"
| rowspan="5" style="background: #D3D3D3"|
| rowspan=2 | 69th (1925–1927)
|- style="height:1.25em"
| rowspan=2 | Frank L. Smith (R)
|- style="height:1.25em"
| rowspan=2 | 70th (1927–1929)
| rowspan="4" |
|- style="height:1.25em"
| rowspan=3 | Otis F. Glenn (R)
|- style="height:2em"
| 71st (1929–1931)
|- style="height:2em"
| rowspan=5 | J. Hamilton Lewis (D)
| rowspan="3" |
| 72nd (1931–1933)
|- style="height:2em"
| 73rd (1933–1935)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | William H. Dieterich (D)
|- style="height:2em"
| 74th (1935–1937)
|- style="height:2em"
| rowspan="5" style="background: #D3D3D3"|
| 75th (1937–1939)
|- style="height:1.25em"
| rowspan=3 | 76th (1939–1941)
| rowspan="5" |
| rowspan=8 | Scott W. Lucas (D)
|- style="height:2em"
| | James M. Slattery (D)
|- style="height:1.25em"
| rowspan=5 | C. Wayland Brooks (R)
|- style="height:2em"
| 77th (1941–1943)
|- style="height:2em"
| rowspan="3" |
| 78th (1943–1945)
|- style="height:2em"
| 79th (1945–1947)
| rowspan="3" style="background: #D3D3D3"|
|- style="height:2em"
| 80th (1947–1949)
|- style="height:2em"
| rowspan=9 | Paul Douglas (D)
| rowspan="3" style="background: #D3D3D3"|
| 81st (1949–1951)
|- style="height:2em"
| 82nd (1951–1953)
| rowspan="3" |
| rowspan=10 | Everett Dirksen (R)
|- style="height:2em"
| 83rd (1953–1955)
|- style="height:2em"
| rowspan="3" |
| 84th (1955–1957)
|- style="height:2em"
| 85th (1957–1959)
| rowspan="3" style="background: #D3D3D3"|
|- style="height:2em"
| 86th (1959–1961)
|- style="height:2em"
| rowspan="3" style="background: #D3D3D3"|
| 87th (1961–1963)
|- style="height:2em"
| 88th (1963–1965)
| rowspan="3" |
|- style="height:2em"
| 89th (1965–1967)
|- style="height:2em"
| rowspan=11 | Charles H. Percy (R)
| rowspan="5" |
| 90th (1967–1969)
|- style="height:1.25em"
| rowspan=3 | 91st (1969–1971)
| rowspan="5" style="background: #D3D3D3"|
|- style="height:2em"
| | Ralph Tyler Smith (R)
|- style="height:1.25em"
| rowspan=6 | Adlai Stevenson III (D)
|- style="height:2em"
| 92nd (1971–1973)
|- style="height:2em"
| rowspan="3" style="background: #D3D3D3"|
| 93rd (1973–1975)
|- style="height:2em"
| 94th (1975–1977)
| rowspan="3" |
|- style="height:2em"
| 95th (1977–1979)
|- style="height:2em"
| rowspan="3" |
| 96th (1979–1981)
|- style="height:2em"
| 97th (1981–1983)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=6 | Alan J. Dixon (D)
|- style="height:2em"
| 98th (1983–1985)
|- style="height:2em"
| rowspan=6 | Paul Simon (D)
| rowspan="3" style="background: #D3D3D3"|
| 99th (1985–1987)
|- style="height:2em"
| 100th (1987–1989)
| rowspan="3" |
|- style="height:2em"
| 101st (1989–1991)
|- style="height:2em"
| rowspan="3" |
| 102nd (1991–1993)
|- style="height:2em"
| 103rd (1993–1995)
| rowspan="3" style="background: #D3D3D3"|
| rowspan=3 | Carol Moseley Braun (D)
|- style="height:2em"
| 104th (1995–1997)
|- style="height:2em"
| rowspan="16" | Dick Durbin (D)
| rowspan="3" style="background: #D3D3D3"|
| 105th (1997–1999)
|- style="height:2em"
| 106th (1999–2001)
| rowspan="3" |
| rowspan=3 | Peter Fitzgerald (R)
|- style="height:2em"
| 107th (2001–2003)
|- style="height:2em"
| rowspan="3" |
| 108th (2003–2005)
|- style="height:2em"
| 109th (2005–2007)
| rowspan="4" style="background: #D3D3D3"|
| rowspan=2 | Barack Obama (D)
|- style="height:2em"
| 110th (2007–2009)
|- style="height:2em"
| rowspan="4" style="background: #D3D3D3"|
| rowspan="2" | 111th (2009–2011)
| | Roland Burris (D)
|- style="height:1.25em"
| rowspan="4" | Mark Kirk (R)
|- style="height:2em"
| 112th (2011–2013)
| rowspan="3" |
|- style="height:2em"
| 113th (2013–2015)
|- style="height:2em"
| rowspan="3" |
| 114th (2015–2017)
|- style="height:2em"
| 115th (2017–2019)
| rowspan="3" style="background: #D3D3D3"|
| rowspan="5" | Tammy Duckworth (D)
|- style="height:2em"
| 116th (2019–2021)
|- style="height:2em"
| rowspan=3 style="background: #D3D3D3"|
| 117th (2021–2023)
|- style="height:2em"
| 118th (2023–2025)
| rowspan="2" |
|- style="height:2em"
| 119th (2025–2027)
|}
United States House of Representatives
1812–1818: 1 non-voting delegate
Starting on December 3, 1812, Illinois Territory sent a non-voting delegate to the House.
{| class=wikitable style="text-align:center"
! Years
! Delegate from<br/>
|- style="height:2.5em"
| December 3, 1812 – August 2, 1813
| | Shadrach Bond <small>(DR)</small>
|- style="height:2.5em"
| November 14, 1814 – March 3, 1817
|| Benjamin Stephenson <small>(DR)</small>
|- style="height:2.5em"
| March 4, 1817 – November 30, 1818
|| Nathaniel Pope <small>(DR)</small>
|}
Part of the area of Illinois Territory became the State of Illinois on December 3, 1818.
1818–1833: 1 seat
Following statehood on December 3, 1818, Illinois had one seat in the House.
{| class=wikitable style="text-align:center"
! Congress
!
|- style="height:2.5em"
| 15th (1818–1819)
| | John McLean <small>(DR)</small>
|- style="height:2.5em"
| 16th (1819–1821)
| rowspan=3 | Daniel Pope Cook <small>(DR)</small>
|- style="height:2.5em"
| 17th (1821–1823)
|- style="height:2.5em"
| 18th (1823–1825)
|- style="height:2.5em"
| 19th (1825–1827)
| | Daniel Pope Cook <small>(NR)</small>
|- style="height:2.5em"
| 20th (1827–1829)
| rowspan=3 | Joseph Duncan <small>(J)</small>
|- style="height:2.5em"
| 21st (1829–1831)
|- style="height:2.5em"
| 22nd (1831–1833)
|}
1833–1843: 3 seats
Following the 1830 census, Illinois was apportioned three seats, all elected via single-member districts.
{| class=wikitable style="text-align:center"
|- style="height:2.5em"
! Congress !! !! !!
|- style="height:2em"
| rowspan=2 | 23rd (1833–1835)
| | Charles Slade <small>(J)</small>
| rowspan=3 | Zadok Casey <small>(J)</small>
| | Joseph Duncan <small>(J)</small>
|- style="height:1.5em"
| rowspan=2 | John Reynolds <small>(J)</small>
| rowspan=2 | William L. May <small>(J)</small>
|- style="height:2.5em"
| 24th (1835–1837)
|- style="height:2.5em"
| 25th (1837–1839)
| | Adam W. Snyder <small>(D)</small>
| rowspan=2 | Zadok Casey <small>(D)</small>
| | William L. May <small>(D)</small>
|- style="height:2.5em"
| 26th (1839–1841)
| rowspan=2 | John Reynolds <small>(D)</small>
| rowspan=2 | John T. Stuart <small>(W)</small>
|- style="height:2.5em"
| 27th (1841–1843)
| | Zadok Casey <small>(ID)</small>
|}
1843–1853: 7 seats
Following the 1840 census, Illinois was apportioned seven seats.
{| class=wikitable style="text-align:center"
|- style="height:2.5em"
! Congress !! !! !! !! !! !! !!
|- style="height:2.5em"
| 28th (1843–1845)
| rowspan=3 | Robert Smith <small>(D)</small>
| rowspan=5 | John A.<br/>McClernand <small>(D)</small>
| rowspan=4 | Orlando B. Ficklin <small>(D)</small>
| rowspan=5 | John Wentworth <small>(D)</small>
| rowspan=3 | Stephen A.<br/>Douglas <small>(D)</small>
| rowspan=3 | Joseph P. Hoge <small>(D)</small>
| | John J. Hardin <small>(W)</small>
|- style="height:2em"
| rowspan=2 | 29th (1845–1847)
| | Edward D. Baker <small>(W)</small>
|- style="height:2em"
| | John Henry <small>(W)</small>
|- style="height:2.5em"
| 30th (1847–1849)
| | Robert Smith <small>(ID)</small>
| rowspan=3 | William Alexander<br/>Richardson <small>(D)</small>
| | Thomas J. Turner <small>(D)</small>
| | Abraham Lincoln <small>(W)</small>
|- style="height:2.5em"
| 31st (1849–1851)
| rowspan=2 | William Henry<br/>Bissell <small>(D)</small>
| | Timothy R. Young <small>(D)</small>
| | Edward D. Baker <small>(W)</small>
| | Thomas L. Harris <small>(D)</small>
|- style="height:2.5em"
| 32nd (1851–1853)
| | Willis Allen <small>(D)</small>
| | Orlando B. Ficklin <small>(D)</small>
| | Richard S. Molony <small>(D)</small>
| | Thompson Campbell <small>(D)</small>
| | Richard Yates <small>(W)</small>
|}
1853–1863: 9 seats
Following the 1850 census, Illinois was apportioned nine seats.
{| class=wikitable style="text-align:center"
|- style="height:2em"
! rowspan=2 | Congress
! colspan=9 | District
|- style="height:2em"
! !! !! !! !! !! !! !! !!
|- style="height:2.5em"
| 33rd
| | Elihu Washburne <small>(W)</small>
| | John Wentworth <small>(D)</small>
| | Jesse O. Norton <small>(W)</small>
| | James Knox <small>(W)</small>
| rowspan=2 | William Alexander<br/>Richardson <small>(D)</small>
| | Richard Yates <small>(W)</small>
| rowspan=3 | James C.<br/>Allen <small>(D)</small>
| | William H. Bissell <small>(ID)</small>
| | Willis Allen <small>(D)</small>
|- style="height:2em"
| rowspan=2 | 34th
| rowspan=7 | Elihu Washburne <small>(R)</small>
| rowspan=2 | James H.<br/>Woodworth <small>(R)</small>
| rowspan=2 | Jesse O. Norton <small>(O)</small>
| rowspan=2 | James Knox <small>(O)</small>
| rowspan=3 | Thomas L. Harris <small>(D)</small>
| rowspan=2 | James L. D.<br/>Morrison <small>(D)</small>
| rowspan=4 | Samuel S.<br/>Marshall <small>(D)</small>
|- style="height:2em"
| | Jacob C. Davis <small>(D)</small>
|- style="height:2em"
| rowspan=2 | 35th
| rowspan=3 | John F.<br/>Farnsworth <small>(R)</small>
| rowspan=5 | Owen Lovejoy <small>(R)</small>
| rowspan=5 | William<br/>Kellogg <small>(R)</small>
| rowspan=3 | Isaac N. Morris <small>(D)</small>
| rowspan=2 | Aaron Shaw <small>(D)</small>
| rowspan=2 | Robert Smith <small>(D)</small>
|- style="height:2em"
| | Charles D. Hodges <small>(D)</small>
|- style="height:2.5em"
| 36th
| rowspan=2 | John A.<br/>McClernand <small>(D)</small>
| rowspan=3 | James Carroll<br/>Robinson <small>(D)</small>
| rowspan=3 | Philip B. Fouke <small>(D)</small>
| rowspan=2 | John A. Logan <small>(D)</small>
|- style="height:2em"
| rowspan=2 | 37th
| rowspan=2 | Isaac N. Arnold <small>(R)</small>
| rowspan=2 | William Alexander<br/>Richardson <small>(D)</small>
|- style="height:2em"
| | Anthony L. Knapp <small>(D)</small>
| | William J. Allen <small>(D)</small>
|}
1863–1873: 14 seats
Following the 1860 census, Illinois was apportioned 14 seats, 13 of which were elected from single member districts and 1 elected at-large statewide.
{| class=wikitable style="text-align:center"
! rowspan=2 | Congress
! colspan=13 | District
! rowspan=2 |
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em"
| rowspan=2 | 38th<br/>
| rowspan=2 | Isaac N.<br/>Arnold <small>(R)</small>
| rowspan=6 | John F.<br/>Farnsworth<br/><small>(R)</small>
| rowspan=4 | Elihu B.<br/>Washburne <small>(R)</small>
| rowspan=2 | Charles M.<br/>Harris <small>(D)</small>
| | Owen<br/>Lovejoy <small>(R)</small>
| rowspan=2 | Jesse O.<br/>Norton <small>(R)</small>
| rowspan=2 | John R.<br/>Eden <small>(D)</small>
| rowspan=2 | John T.<br/>Stuart <small>(D)</small>
| rowspan=4 | Lewis W.<br/>Ross <small>(D)</small>
| rowspan=2 | Anthony L.<br/>Knapp <small>(D)</small>
| rowspan=2 | James Carroll<br/>Robinson <small>(D)</small>
| rowspan=2 | William Ralls<br/>Morrison <small>(D)</small>
| rowspan=2 | William J.<br/>Allen <small>(D)</small>
| rowspan=2 | James C.<br/>Allen <small>(D)</small>
|- style="height:2em"
| rowspan=4 | Ebon C.<br/>Ingersoll <small>(R)</small>
|- style="height:2em"
| 39th<br/>
| | John<br/>Wentworth <small>(R)</small>
| rowspan=2 | Abner C.<br/>Harding <small>(R)</small>
| rowspan=3 | Burton C.<br/>Cook <small>(R)</small>
| rowspan=2 | Henry P. H.<br/>Bromwell <small>(R)</small>
| rowspan=3 | Shelby M.<br/>Cullom <small>(R)</small>
| | Anthony<br/>Thornton <small>(D)</small>
| rowspan=4 | Samuel S.<br/>Marshall <small>(D)</small>
| rowspan=2 | Jehu<br/>Baker <small>(R)</small>
| | Andrew J.<br/>Kuykendall <small>(R)</small>
| | Samuel W.<br/>Moulton <small>(R)</small>
|- style="height:2em"
| 40th<br/>
| rowspan=2 | Norman B.<br/>Judd <small>(R)</small>
| rowspan=2 | Albert G.<br/>Burr <small>(D)</small>
| | Green B.<br/>Raum <small>(R)</small>
| rowspan=2 | John A.<br/>Logan <small>(R)</small>
|- style="height:2em"
| 41st<br/>
| rowspan=2 | Horatio C.<br/>Burchard <small>(R)</small>
| rowspan=2 | John B.<br/>Hawley <small>(R)</small>
| rowspan=2 | Jesse H.<br/>Moore <small>(R)</small>
| rowspan=2 | Thompson W.<br/>McNeely <small>(D)</small>
| rowspan=2 | John B.<br/>Hay <small>(R)</small>
| rowspan=2 | John M.<br/>Crebs <small>(D)</small>
|- style="height:2em"
| 42nd<br/>
| | Charles B.<br/>Farwell <small>(R)</small>
| | Bradford N.<br/>Stevens <small>(D)</small>
| | Henry<br/>Snapp <small>(R)</small>
| | James Carroll<br/>Robinson <small>(D)</small>
| | Edward Y.<br/>Rice <small>(D)</small>
| | John Lourie<br/>Beveridge <small>(R)</small>
|}
1873–1883: 19 seats
Following the 1870 census, Illinois was apportioned 19 seats, all elected via single member districts.
{| class=wikitable style="text-align:center"
! rowspan=2 | Cong­ress
! colspan=10 | District
! colspan=9 | District
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em"
| 43rd<br/>(1873–1875)
| | John Blake Rice <small>(R)</small>
| | Jasper D. Ward <small>(R)</small>
| rowspan=2 | Charles B. Farwell <small>(R)</small>
| rowspan=3 | Stephen A. Hurlbut <small>(R)</small>
| rowspan=4 | Horatio C. Burchard <small>(R)</small>
| | John B. Hawley <small>(R)</small>
| | Franklin Corwin <small>(R)</small>
| rowspan=5 | Greenbury L. Fort <small>(R)</small>
| | Granville Barrere <small>(R)</small>
| | William H. Ray <small>(R)</small>
| | Robert M. Knapp <small>(D)</small>
| | James Carroll<br/>Robinson <small>(D)</small>
| | John McNulta <small>(R)</small>
| rowspan=7 | Joe Cannon <small>(R)</small>
| rowspan=4 | John R. Eden <small>(D)</small>
| | James Stewart<br/>Martin <small>(R)</small>
| rowspan=7 | William Ralls<br/>Morrison <small>(D)</small>
| | Isaac Clements <small>(R)</small>
| | Samuel S.<br/>Marshall <small>(D)</small>
|- style="height:2em"
| rowspan=2 | 44th<br/>(1875–1877)
| rowspan=2 | Bernard G. Caulfield <small>(D)</small>
| rowspan=3 | Carter Harrison III <small>(D)</small>
| rowspan=6 | Thomas J.<br/>Henderson <small>(R)</small>
| rowspan=2 | Alexander Campbell <small>(I)</small>
| rowspan=2 | Richard H. Whiting <small>(R)</small>
| rowspan=2 | John C. Bagby <small>(D)</small>
| rowspan=2 | Scott Wike <small>(D)</small>
| rowspan=6 | William<br/>Springer <small>(D)</small>
| rowspan=2 | Adlai Stevenson I <small>(D)</small>
| rowspan=6 | William A. J.<br/>Sparks <small>(D)</small>
| rowspan=3 | William Hartzell <small>(D)</small>
| rowspan=2 | William B.<br/>Anderson <small>(I)</small>
|- style="height:2em"
| | John V. Le Moyne <small>(D)</small>
|- style="height:2em"
| 45th<br/>(1877–1879)
| rowspan=4 | William Aldrich <small>(R)</small>
| | Lorenzo Brentano <small>(R)</small>
| | William Lathrop <small>(R)</small>
| rowspan=2 | Philip C. Hayes <small>(R)</small>
| rowspan=2 | Thomas A. Boyd <small>(R)</small>
| rowspan=4 | Benjamin F. Marsh <small>(R)</small>
| | Robert M. Knapp <small>(D)</small>
| | Thomas F. Tipton <small>(R)</small>
| rowspan=4 | Richard W.<br/>Townshend <small>(D)</small>
|- style="height:2em"
| 46th<br/>(1879–1881)
| rowspan=3 | George R. Davis <small>(R)</small>
| | Hiram Barber Jr. <small>(R)</small>
| rowspan=3 | John C. Sherwin <small>(R)</small>
| rowspan=2 | Robert M. A. Hawk <small>(R)</small>
| rowspan=3 | James W. Singleton <small>(D)</small>
| | Adlai Stevenson I <small>(D)</small>
| |Albert P. Forsythe <small>(GB)</small>
| rowspan=3 | John R. Thomas <small>(R)</small>
|- style="height:2em"
| rowspan=2 | 47th<br/>(1881–1883)
| rowspan=2 | Charles B. Farwell <small>(R)</small>
| rowspan=2 | William Cullen <small>(R)</small>
| rowspan=2 | Lewis E. Payson <small>(R)</small>
| rowspan=2 | John H. Lewis <small>(R)</small>
| rowspan=2 | Dietrich C. Smith <small>(R)</small>
| rowspan=2 | Samuel W. Moulton <small>(D)</small>
|- style="height:2em"
| | Robert R. Hitt <small>(R)</small>
|}
1883–1893: 20 seats
Following the 1860 census, Illinois was apportioned 20 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Cong­ress
! colspan=10 | District
! colspan=10 | District
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em"
| 48th (1883–1885)
| rowspan=3 | Ransom W. Dunham <small>(R)</small>
| | John F. Finerty <small>(ID)</small>
| | George R. Davis <small>(R)</small>
| rowspan=4 | George E. Adams <small>(R)</small>
| | Reuben Ellwood <small>(R)</small>
| rowspan=5 | Robert R. Hitt <small>(R)</small>
| rowspan=5 | Thomas J.<br/>Hender­son <small>(R)</small>
| | William Cullen <small>(R)</small>
| rowspan=4 | Lewis E. Payson <small>(R)</small>
| rowspan=2 | Nicholas E. Worthing­ton <small>(D)</small>
| rowspan=2 | William H. Neece <small>(D)</small>
| rowspan=2 | James M. Riggs <small>(D)</small>
| rowspan=5 | William Springer <small>(D)</small>
| rowspan=4 | Jonathan H. Rowell <small>(R)</small>
| rowspan=4 | Joe Cannon <small>(R)</small>
| | Aaron Shaw <small>(D)</small>
| | Samuel W. Moulton <small>(D)</small>
| rowspan=2 | William Ralls Morrison <small>(D)</small>
| rowspan=3 | Richard W. Towns­hend <small>(D)</small>
| rowspan=3 | John R. Thomas <small>(R)</small>
|- style="height:2em"
| 49th (1885–1887)
| rowspan=3 | Frank Lawler <small>(D)</small>
| | James Hugh Ward <small>(D)</small>
| rowspan=4 | Albert J. Hopkins <small>(R)</small>
| rowspan=2 | Ralph Plumb <small>(R)</small>
| rowspan=2 | Silas Z. Landes <small>(D)</small>
| | John R. Eden <small>(D)</small>
|- style="height:2em"
| 50th (1887–1889)
| rowspan=2 | William E. Mason <small>(R)</small>
| rowspan=3 | Philip S. Post <small>(R)</small>
| rowspan=2 | William H. Gest <small>(R)</small>
| | George A. Ander­son <small>(D)</small>
| rowspan=3 | Edward Lane <small>(D)</small>
| | Jehu Baker <small>(R)</small>
|- style="height:2em"
| 51st (1889–1891)
| rowspan=2 | Abner Taylor <small>(R)</small>
| | Charles A. Hill <small>(R)</small>
| rowspan=2 | Scott Wike <small>(D)</small>
| rowspan=2 | George W. Fithian <small>(D)</small>
| rowspan=2 | William S. Forman <small>(D)</small>
| rowspan=2 | James R. Williams <small>(D)</small>
| rowspan=2 | George W. Smith <small>(R)</small>
|- style="height:2em"
| 52nd (1891–1893)
| | Lawrence McGann <small>(D)</small>
| | Allan C. Durborow Jr. <small>(D)</small>
| | Walter C. New­berry <small>(D)</small>
| | Lewis Steward <small>(D)</small>
| | Herman W. Snow <small>(D)</small>
| | Benjamin T. Cable <small>(D)</small>
| | Owen Scott <small>(D)</small>
| | Samuel T. Busey <small>(D)</small>
|}
1893–1903: 22 seats
Following the 1890 census, Illinois was apportioned 22 seats. Until 1895, 20 seats were elected from single member districts and 2 were elected at-large statewide. In 1895, Illinois redistricted all of its seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Cong­ress
! colspan=10 | District
! colspan=10 | District
! colspan=2 |
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
! Seat A
! Seat B
|- style="height:2em"
| 53rd (1893–1895)
| rowspan=3 | J. Frank Aldrich <small>(R)</small>
| | Lawrence McGann <small>(D)</small>
| | Allan C. Durborow Jr. <small>(D)</small>
| | Julius Goldzier <small>(D)</small>
| | Albert J. Hopkins <small>(R)</small>
| | Robert R. Hitt <small>(R)</small>
| | Thomas J.<br/>Hender­son <small>(R)</small>
| | Robert A. Childs <small>(R)</small>
| | Hamilton K. Wheeler <small>(R)</small>
| | Philip S. Post <small>(R)</small>
| | Benjamin F. Marsh <small>(R)</small>
| | John J.<br/>McDan­nold <small>(D)</small>
| | William Springer <small>(D)</small>
| | Benjamin F. Funk <small>(R)</small>
| | Joe Cannon <small>(R)</small>
| | George W. Fithian <small>(D)</small>
| | Edward Lane <small>(D)</small>
| | William S. Forman <small>(D)</small>
| | James R. Williams <small>(D)</small>
| | George W. Smith <small>(R)</small>
| | John C. Black <small>(D)</small>
| | Andrew J. Hunter <small>(D)</small>
|- style="height:2em"
| rowspan=2 | 54th (1895–1897)
| rowspan=4 | William Lorimer <small>(R)</small>
| | Lawrence McGann <small>(D)</small>
| rowspan=2 | Charles W. Wood­man <small>(R)</small>
| rowspan=3 | George E. White <small>(R)</small>
| rowspan=2 | Edward D. Cooke <small>(R)</small>
| rowspan=5 | George E. Foss <small>(R)</small>
| rowspan=5 | Albert J. Hopkins <small>(R)</small>
| rowspan=5 | Robert R. Hitt <small>(R)</small>
| rowspan=5 | George W. Prince <small>(R)</small>
| rowspan=5 | Walter Reeves <small>(R)</small>
| rowspan=5 | Joe Cannon <small>(R)</small>
| rowspan=5 | Vespasian Warner <small>(R)</small>
| rowspan=5 | Joseph V. Graff <small>(R)</small>
| rowspan=4 | Benjamin F. Marsh <small>(R)</small>
| | Finis E. Downing <small>(D)</small>
| rowspan=3 | James A. Connolly <small>(R)</small>
| | Frederick Remann <small>(R)</small>
| rowspan=2 | Benson Wood <small>(R)</small>
| rowspan=2 | Orlando Burrell <small>(R)</small>
!
!
|- style="height:2em"
| rowspan=2 | Hugh R. Belknap <small>(R)</small>
| | John I. Rinaker <small>(R)</small>
| | William Hadley <small>(R)</small>
| | Everett Murphy <small>(R)</small>
| rowspan=4 | George W. Smith <small>(R)</small>
|- style="height:2em"
| 55th (1897–1899)
| rowspan=3 | James Robert Mann <small>(R)</small>
| | Daniel W. Mills <small>(R)</small>
| rowspan=3 | Henry S. Boutell <small>(R)</small>
| | William H. Hinrichsen <small>(D)</small>
| rowspan=3 | Thomas M. Jett <small>(D)</small>
| | Andrew J. Hunter <small>(D)</small>
| | James R. Campbell <small>(D)</small>
| | Jehu Baker <small>(D)</small>
|- style="height:2em"
| 56th (1899–1901)
| rowspan=2 | George Peter Foster <small>(D)</small>
| | Thomas Cusack <small>(D)</small>
| | Edward T. Noonan <small>(D)</small>
| | William E. Williams <small>(D)</small>
| rowspan=2 | Ben F. Caldwell <small>(D)</small>
| rowspan=2 | Joseph B. Crowley <small>(D)</small>
| rowspan=2 | James R. Williams <small>(D)</small>
| | William Roden­berg <small>(R)</small>
|- style="height:2em"
| 57th (1901–1903)
| | John J. Feely <small>(D)</small>
| | James McAnd­rews <small>(D)</small>
| | William F. Mahoney <small>(D)</small>
| | J. Ross Mickey <small>(D)</small>
| | Thomas J. Selby <small>(D)</small>
| | Fred J. Kern <small>(D)</small>
|}
1903–1913: 25 seats
Following the 1900 census, Illinois was apportioned 25 seats.
{| class="wikitable" style="float:left; margin:0; margin-right:-0.5px; margin-top:14px; text-align:center;"
|- style="white-space:nowrap; height:4.04em;"
! Congress
|- style="white-space:nowrap; height:3em;"
|<br/>(1903–1905)
|- style="white-space:nowrap; height:3em"
|<br/>(1905–1907)
|- style="white-space:nowrap; height:3em"
|<br/>(1907–1909)
|- style="white-space:nowrap; height:3em"
|<br/>(1909–1911)
|- style="white-space:nowrap; height:3em"
|<br/>(1911–1913)
|}
<div style="overflow-x:auto; white-space:nowrap;">
{| class=wikitable style="text-align:center"
! colspan=10 | District
! colspan=10 | District
! colspan=5 | District
! rowspan=2 | Congress
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em"
| | Martin<br/>Emerich <small>(D)</small>
| rowspan=6 | James<br/>R.<br/>Mann<br/><small>(R)</small>
| rowspan=6 | William<br/>W.<br/>Wilson<br/><small>(R)</small>
| | George P.<br/>Foster <small>(D)</small>
| | James<br/>McAndrews <small>(D)</small>
| rowspan=4 | William<br/>Lorimer<br/><small>(R)</small>
| rowspan=4 | Philip<br/>Knopf <small>(R)</small>
| | William F.<br/>Mahoney <small>(D)</small>
| rowspan=5 | Henry<br/>S.<br/>Boutell<br/><small>(R)</small>
| rowspan=6 | George<br/>E.<br/>Foss<br/><small>(R)</small>
| rowspan=5 | Howard M.<br/>Snapp <small>(R)</small>
| rowspan=6 | Charles<br/>E.<br/>Fuller<br/><small>(R)</small>
| rowspan=2 | Robert R.<br/>Hitt <small>(R)</small>
| | Benjamin F.<br/>Marsh <small>(R)</small>
| rowspan=6 | George<br/>W.<br/>Prince<br/><small>(R)</small>
| rowspan=5 | Joseph V.<br/>Graff <small>(R)</small>
| rowspan=6 | John<br/>A.<br/>Sterling<br/><small>(R)</small>
| rowspan=6 | Joe<br/>Cannon<br/><small>(R)</small>
| | Vespasian<br/>Warner <small>(R)</small>
| rowspan=6 | Henry<br/>T.<br/>Rainey<br/><small>(D)</small>
| | Ben F.<br/>Caldwell <small>(D)</small>
| rowspan=6 | William A.<br/>Rodenberg<br/><small>(R)</small>
| | Joseph B.<br/>Crowley <small>(D)</small>
| | James R.<br/>Williams <small>(D)</small>
| rowspan=3 | George W.<br/>Smith <small>(R)</small>
| 58th<br/>(1903–1905)
|- style="height:2em"
| rowspan=5 | Martin B.<br/>Madden<br/><small>(R)</small>
| | Charles S.<br/>Wharton <small>(R)</small>
| | Anthony<br/>Michalek <small>(R)</small>
| rowspan=3 | Charles<br/>McGavin <small>(R)</small>
| rowspan=5 | James<br/>McKinney<br/><small>(R)</small>
| rowspan=5 | William B.<br/>McKinley<br/><small>(R)</small>
| | Zeno J.<br/>Rives <small>(R)</small>
| | Frank S.<br/>Dickson <small>(R)</small>
| rowspan=4 | Pleasant T.<br/>Chapman<br/><small>(R)</small>
| 59th<br/>(1905–1907)
|- style="height:1.5em"
| rowspan=4 | James T.<br/>McDermott<br/><small>(D)</small>
| rowspan=4 | Adolph J.<br/>Sabath <small>(D)</small>
| rowspan=3 | Frank O.<br/>Lowden<br/><small>(R)</small>
| rowspan=2 | Ben F.<br/>Caldwell <small>(D)</small>
| rowspan=4 | Martin D.<br/>Foster <small>(D)</small>
| rowspan=2 | 60th<br/>(1907–1909)
|- style="height:1.5em"
| rowspan=3 | Napoleon B.<br/>Thistlewood<br/><small>(R)</small>
|- style="height:2em"
| | William<br/>Moxley <small>(R)</small>
| | Frederick<br/>Lundin <small>(R)</small>
| rowspan=2 | Thomas<br/>Gallagher<br/><small>(D)</small>
| rowspan=2 | James M.<br/>Graham<br/><small>(D)</small>
| 61st<br/>(1909–1911)
|- style="height:2em"
| | Edmund J.<br/>Stack <small>(D)</small>
| | Frank<br/>Buchanan <small>(D)</small>
| | Lynden<br/>Evans <small>(D)</small>
| | Ira C.<br/>Copley <small>(R)</small>
| | John C.<br/>McKenzie <small>(R)</small>
| | Claude U.<br/>Stone <small>(D)</small>
| | H. Robert<br/>Fowler <small>(D)</small>
| 62nd<br/>(1911–1913)
|}
</div>
1913–1943: 27 seats
Following the 1910 census, Illinois was apportioned 27 seats, 25 of which were elected from single member districts and 2 were elected at-large statewide.
{| class="wikitable" style="float:left; margin:0; margin-right:-0.5px; margin-top:14px; text-align:center;"
|- style="white-space:nowrap; height:4.06em;"
! Congress
|- style="white-space:nowrap; height:3em;"
|<br/>(1913–1915)
|- style="white-space:nowrap; height:3em"
| <br/>(1915–1917)
|- style="white-space:nowrap; height:4.08em"
|<br/>(1917–1919)
|- style="white-space:nowrap; height:3em"
|<br/>(1919–1921)
|- style="white-space:nowrap; height:3em"
|<br/>(1921–1923)
|- style="white-space:nowrap; height:3em;"
|<br/>(1923–1925)
|- style="white-space:nowrap; height:3em"
|<br/>(1925–1927)
|- style="white-space:nowrap; height:3em"
|<br/>(1927–1929)
|- style="white-space:nowrap; height:3em"
|<br/>(1929–1931)
|- style="white-space:nowrap; height:4.08em"
|<br/>(1931–1933)
|- style="white-space:nowrap; height:3em;"
|<br/>(1933–1935)
|- style="white-space:nowrap; height:3em"
|<br/>(1935–1937)
|- style="white-space:nowrap; height:3em"
|<br/>(1937–1939)
|- style="white-space:nowrap; height:3em"
|<br/>(1939–1941)
|- style="white-space:nowrap; height:3em"
|<br/>(1941–1943)
|- style="white-space:nowrap; height:4.06em;"
! Congress
|}
<div style="overflow-x:auto; white-space:nowrap;">
{| class=wikitable style="text-align:center"
! colspan=10 | District
! colspan=10 | District
! colspan=5 | District
! colspan=2 |
! rowspan=2 | Congress
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
! Seat A
! Seat B
|- style="height:2em"
| rowspan=9 | Martin<br/>B.<br/>Madden<br/><small>(R)</small>
| rowspan=6 | James<br/>Robert<br/>Mann <small>(R)</small>
| | George E.<br/>Gorman <small>(D)</small>
| rowspan=2 | James T.<br/>McDermott<br/><small>(D)</small>
| rowspan=17 | Adolph<br/>J.<br/>Sabath<br/><small>(D)</small>
| rowspan=5 | James<br/>McAndrews<br/><small>(D)</small>
| rowspan=2 | Frank<br/>Buchanan<br/><small>(D)</small>
| rowspan=5 | Thomas<br/>Gallagher <small>(D)</small>
| rowspan=13 | Frederick<br/>A.<br/>Britten <small>(R)</small>
| | Charles Thom-<br/>son <small>(Prog)</small>
| | Ira C.<br/>Copley <small>(R)</small>
| | William Hine-<br/>baugh <small>(Prog)</small>
| rowspan=7 | John C.<br/>McKenzie<br/><small>(R)</small>
| rowspan=2 | Clyde H.<br/>Tavenner<br/><small>(D)</small>
| | Stephen A.<br/>Hoxworth <small>(D)</small>
| rowspan=2 | Claude<br/>U.<br/>Stone<br/><small>(D)</small>
| | Louis<br/>FitzHenry <small>(D)</small>
| | Frank T.<br/>O'Hair <small>(D)</small>
| | Charles M.<br/>Borchers <small>(D)</small>
| rowspan=5 | Henry<br/>T.<br/>Rainey<br/><small>(D)</small>
| | James M.<br/>Graham <small>(D)</small>
| | William N.<br/>Baltz <small>(D)</small>
| rowspan=4 | Martin<br/>D.<br/>Foster<br/><small>(D)</small>
| | H. Robert<br/>Fowler <small>(D)</small>
| | Robert P.<br/>Hill <small>(D)</small>
| | Lawrence B.<br/>Stringer <small>(D)</small>
| rowspan=2 | William E.<br/>Williams <small>(D)</small>
| 63rd<br/>(1913–1915)
|- style="height:2em"
| rowspan=4 | William<br/>Warfield<br/>Wilson<br/><small>(R)</small>
| rowspan=3 | George<br/>E.<br/>Foss <small>(R)</small>
| | Ira C.<br/>Copley <small>(Prog)</small>
| rowspan=7 | Charles<br/>Eugene<br/>Fuller <small>(R)</small>
| rowspan=8 | Edward<br/>John<br/>King <small>(R)</small>
| rowspan=3 | John A.<br/>Sterling <small>(R)</small>
| rowspan=5 | Joe<br/>Cannon<br/><small>(R)</small>
| rowspan=4 | William B.<br/>McKinley<br/><small>(R)</small>
| rowspan=5 | Loren E.<br/>Wheeler <small>(R)</small>
| rowspan=5 | William A.<br/>Rodenberg<br/><small>(R)</small>
| rowspan=9 | Thomas<br/>Sutler<br/>Williams<br/><small>(R)</small>
| rowspan=9 | Edward E.<br/>Denison<br/><small>(R)</small>
| | Burnett M.<br/>Chiperfield <small>(R)</small>
| 64th<br/>(1915–1917)
|- style="height:2em"
| | C. Martin <small>(D)</small>
| rowspan=3 | Niels<br/>Juul <small>(R)</small>
| rowspan=4 | Ira C.<br/>Copley <small>(R)</small>
| rowspan=5 | William J.<br/>Graham<br/><small>(R)</small>
| rowspan=4 | Clifford<br/>C.<br/>Ireland<br/><small>(R)</small>
| rowspan=2 | Medill<br/>McCormick <small>(R)</small>
| rowspan=3 | William E.<br/>Mason <small>(R)</small>
| rowspan=2 | 65th<br/>(1917–1919)
|- style="height:2em"
| rowspan=3 | John W.<br/>Rainey <small>(D)</small>
|- style="height:2em"
| rowspan=8 | Carl R.<br/>Chindblom <small>(R)</small>
| | Frank L.<br/>Smith <small>(R)</small>
| rowspan=2 | Edwin B.<br/>Brooks<br/><small>(R)</small>
| rowspan=8 | Richard<br/>Yates Jr. <small>(R)</small>
| 66th<br/>(1919–1921)
|- style="height:2em"
| rowspan=5 | Elliott W.<br/>Sproul <small>(R)</small>
| | John J.<br/>Gorman <small>(R)</small>
| rowspan=5 | M. Alfred<br/>Michaelson<br/><small>(R)</small>
| rowspan=5 | Stanley H.<br/>Kunz <small>(D)</small>
| rowspan=3 | Frank H.<br/>Funk <small>(R)</small>
| rowspan=2 | Allen F.<br/>Moore <small>(R)</small>
| | Guy L.<br/>Shaw <small>(R)</small>
| | Winnifred<br/>Mason Huck <small>(R)</small>
| 67th<br/>(1921–1923)
|- style="height:2em"
| rowspan=6 | Morton D.<br/>Hull <small>(R)</small>
| rowspan=4 | Thomas A.<br/>Doyle <small>(D)</small>
| | James R.<br/>Buckley <small>(D)</small>
| rowspan=7 | Frank R.<br/>Reid <small>(R)</small>
| rowspan=6 | William<br/>E. Hull<br/><small>(R)</small>
| rowspan=6 | William P.<br/>Holaday<br/><small>(R)</small>
| rowspan=7 | Henry<br/>T.<br/>Rainey<br/><small>(D)</small>
| | James Earl<br/>Major <small>(D)</small>
| | Edward E.<br/>Miller <small>(R)</small>
| rowspan=9 | William<br/>W.<br/>Arnold<br/><small>(D)</small>
| rowspan=3 | Henry R.<br/>Rathbone <small>(R)</small>
| 68th<br/>(1923–1925)
|- style="height:2em"
| | John J.<br/>Gorman <small>(R)</small>
| rowspan=5 | William<br/>Richard<br/>Johnson<br/><small>(R)</small>
| rowspan=5 | John<br/>Clayton<br/>Allen <small>(R)</small>
| rowspan=5 | Charles<br/>Adkins <small>(R)</small>
| | Loren E.<br/>Wheeler <small>(R)</small>
| rowspan=3 | Edward M.<br/>Irwin <small>(R)</small>
| 69th<br/>(1925–1927)
|- style="height:2em"
| rowspan=4 | James T.<br/>Igoe <small>(D)</small>
| rowspan=6 | John T.<br/>Buckbee <small>(R)</small>
| rowspan=4 | Homer W.<br/>Hall <small>(R)</small>
| | James Earl<br/>Major <small>(D)</small>
| 70th<br/>(1927–1929)
|- style="height:2em"
| rowspan=4 | Oscar<br/>Stanton<br/>De<br/>Priest<br/><small>(R)</small>
| rowspan=3 | Burnett M.<br/>Chiperfield<br/><small>(R)</small>
| | Frank M.<br/>Ramey <small>(R)</small>
| | Ruth Hanna<br/>McCormick <small>(R)</small>
| 71st<br/>(1929–1931)
|- style="height:2em"
| rowspan=7 | Edward A.<br/>Kelly <small>(D)</small>
| rowspan=7 | Harry P.<br/>Beam <small>(D)</small>
| rowspan=7 | Leonard W.<br/>Schuetz <small>(D)</small>
| | P. C. Granata <small>(R)</small>
| rowspan=3 | James<br/>Earl<br/>Major <small>(D)</small>
| rowspan=2 | Charles A.<br/>Karch <small>(D)</small>
| rowspan=6 | Claude V.<br/>Parsons <small>(D)</small>
| rowspan=6 | Kent E.<br/>Keller <small>(D)</small>
| rowspan=2 | William H.<br/>Dieterich <small>(D)</small>
| rowspan=2 | 72nd<br/>(1931–1933)
|- style="height:2em"
| | S. H. Kunz <small>(D)</small>
|- style="height:2em"
| | P. H.<br/>Moynihan <small>(R)</small>
| rowspan=3 | Thomas J.<br/>O'Brien <small>(D)</small>
| rowspan=5 | Leo<br/>Kocialkowski<br/><small>(D)</small>
| | James<br/>Simpson Jr. <small>(R)</small>
| rowspan=5 | Leo E.<br/>Allen <small>(R)</small>
| rowspan=3 | Chester C.<br/>Thompson<br/><small>(D)</small>
| rowspan=2 | J. Leroy<br/>Adair <small>(D)</small>
| rowspan=5 | Everett<br/>Dirksen<br/><small>(R)</small>
| | Frank<br/>Gillespie <small>(D)</small>
| rowspan=3 | James A.<br/>Meeks <small>(D)</small>
| rowspan=2 | Donald C.<br/>Dobbins <small>(D)</small>
| rowspan=5 | Edwin M.<br/>Schaefer<br/><small>(D)</small>
| rowspan=2 | Martin A.<br/>Brennan <small>(D)</small>
| | Walter<br/>Nesbit <small>(D)</small>
| 73rd<br/>(1933–1935)
|- style="height:2em"
| rowspan=4 | Arthur<br/>Wergs<br/>Mitchell<br/><small>(D)</small>
| rowspan=4 | Raymond S.<br/>McKeough<br/><small>(D)</small>
| rowspan=3 | James<br/>McAndrews<br/><small>(D)</small>
| rowspan=3 | Ralph E.<br/>Church <small>(R)</small>
| rowspan=4 | Chauncey W.<br/>Reed <small>(R)</small>
| rowspan=4 | Leslie C.<br/>Arends <small>(R)</small>
| rowspan=2 | Scott W.<br/>Lucas <small>(D)</small>
| | Harry H.<br/>Mason <small>(D)</small>
| | Michael L.<br/>Igoe <small>(D)</small>
| 74th<br/>(1935–1937)
|- style="height:2em"
| rowspan=3 | Noah M.<br/>Mason <small>(R)</small>
| | Lewis L.<br/>Boyer <small>(D)</small>
| | Hugh M.<br/>Rigney <small>(D)</small>
| rowspan=2 | Frank W.<br/>Fries <small>(D)</small>
| | Edwin V.<br/>Champion <small>(D)</small>
| | Lewis M.<br/>Long <small>(D)</small>
| 75th<br/>(1937–1939)
|- style="height:2em"
| rowspan=2 | A. F.<br/>Maciejewski<br/><small>(D)</small>
| rowspan=2 | Anton J.<br/>Johnson<br/><small>(R)</small>
| rowspan=2 | Robert B.<br/>Chiperfield<br/><small>(R)</small>
| rowspan=2 | Jessie<br/>Sumner<br/><small>(R)</small>
| rowspan=2 | Bill<br/>Wheat <small>(R)</small>
| rowspan=2 | James M.<br/>Barnes <small>(D)</small>
| rowspan=2 | Laurence<br/>F.<br/>Arnold<br/><small>(D)</small>
| | John C.<br/>Martin <small>(D)</small>
| | T. V.<br/>Smith <small>(D)</small>
| 76th<br/>(1939–1941)
|- style="height:2em"
| | Charles S.<br/>Dewey <small>(R)</small>
| | George A.<br/>Paddock <small>(R)</small>
| | George Evan<br/>Howell <small>(R)</small>
| | James V.<br/>Heidinger <small>(R)</small>
| | C. W.<br/>Bishop <small>(R)</small>
| | Stephen A.<br/>Day <small>(R)</small>
| | William<br/>Stratton <small>(R)</small>
| 77th<br/>(1941–1943)
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
! Seat A
! Seat B
! rowspan=2 | Congress
|-
! colspan=10 | District
! colspan=10 | District
! colspan=5 | District
! colspan=2 |
|}
</div>
1943–1953: 26 seats
Following the 1940 census, Illinois was apportioned 26 seats. Until 1949, 25 seats were elected from single member districts and 1 was elected at-large statewide. From 1949, all 26 seats were redistricted.
{| class="wikitable" style="float:left; margin:0; margin-right:-0.5px; margin-top:14px; text-align:center;"
|- style="white-space:nowrap; height:4.1em;"
! Congress
|- style="white-space:nowrap; height:3em;"
|<br/>(1943–1945)
|- style="white-space:nowrap; height:3em"
| <br/>(1945–1947)
|- style="white-space:nowrap; height:3em"
|<br/>(1947–1949)
|- style="white-space:nowrap; height:4.04em"
|<br/>(1949–1951)
|- style="white-space:nowrap; height:3em"
|<br/>(1951–1953)
|}
<div style="overflow-x:auto; white-space:nowrap;">
{| class=wikitable style="text-align:center"
! colspan=10 | District
! colspan=10 | District
! colspan=6 | District
! rowspan=2 | Congress
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em"
| rowspan=6 | William<br/>L.<br/>Dawson<br/><small>(D)</small>
| rowspan=2 | William<br/>A.<br/>Rowan<br/><small>(D)</small>
| | Fred E.<br/>Busbey <small>(R)</small>
| rowspan=3 | Martin<br/>Gorski <small>(D)</small>
| rowspan=3 | Adolph J.<br/>Sabath <small>(D)</small>
| rowspan=6 | Thomas<br/>J.<br/>O'Brien<br/><small>(D)</small>
| | Leonard W.<br/>Schuetz <small>(D)</small>
| rowspan=6 | Thomas<br/>S.<br/>Gordon<br/><small>(D)</small>
| | Charles S.<br/>Dewey <small>(R)</small>
| rowspan=3 | Ralph E.<br/>Church<br/><small>(R)</small>
| rowspan=3 | Chauncey<br/>W.<br/>Reed <small>(R)</small>
| rowspan=3 | Noah M.<br/>Mason<br/><small>(R)</small>
| rowspan=3 | Leo E.<br/>Allen <small>(R)</small>
| rowspan=3 | Anton J.<br/>Johnson<br/><small>(R)</small>
| rowspan=3 | Robert B.<br/>Chiperfield<br/><small>(R)</small>
| rowspan=3 | Everett<br/>Dirksen<br/><small>(R)</small>
| rowspan=6 | Leslie<br/>C.<br/>Arends<br/><small>(R)</small>
| rowspan=2 | Jessie<br/>Sumner<br/><small>(R)</small>
| | William H.<br/>Wheat <small>(R)</small>
| rowspan=6 | Sid<br/>Simpson<br/><small>(R)</small>
| rowspan=3 | George<br/>Evan<br/>Howell<br/><small>(R)</small>
| | Calvin D.<br/>Johnson <small>(R)</small>
| rowspan=3 | Charles<br/>W.<br/>Vursell<br/><small>(R)</small>
| rowspan=2 | James V.<br/>Heidinger<br/><small>(R)</small>
| rowspan=3 | C. W.<br/>Bishop<br/><small>(R)</small>
| | Stephen A.<br/>Day <small>(R)</small>
| 78th<br/>(1943–1945)
|- style="height:2em"
| | Edward A.<br/>Kelly <small>(D)</small>
| | William W.<br/>Link <small>(D)</small>
| | Alexander J.<br/>Resa <small>(D)</small>
| rowspan=2 | Rolla C.<br/>McMillen<br/><small>(R)</small>
| rowspan=2 | Melvin<br/>Price <small>(D)</small>
| | Emily Taft<br/>Douglas <small>(D)</small>
| 79th<br/>(1945–1947)
|- style="height:2em"
| | Richard B.<br/>Vail <small>(R)</small>
| | Fred E.<br/>Busbey <small>(R)</small>
| | Thomas L.<br/>Owens <small>(R)</small>
| | Robert<br/>Twyman <small>(R)</small>
| | Edward H.<br/>Jenison <small>(R)</small>
| | Roy<br/>Clippinger <small>(R)</small>
| | William<br/>Stratton <small>(R)</small>
| 80th<br/>(1947–1949)
|- style="height:2em"
| rowspan=2 | Barratt<br/>O'Hara <small>(D)</small>
| rowspan=2 | Neil J.<br/>Linehan <small>(D)</small>
| rowspan=2 | James V.<br/>Buckley <small>(D)</small>
| rowspan=2 | Martin<br/>Gorski <small>(D)</small>
| rowspan=3 | Adolph J.<br/>Sabath <small>(D)</small>
| rowspan=3 | Sidney R.<br/>Yates <small>(D)</small>
| rowspan=3 | Richard<br/>W.<br/>Hoffman<br/><small>(R)</small>
| rowspan=2 | Chester A.<br/>Chesney <small>(D)</small>
| rowspan=3 | Edgar<br/>A.<br/>Jonas<br/><small>(R)</small>
| rowspan=2 | Ralph E.<br/>Church <small>(R)</small>
| rowspan=3 | Chauncey<br/>W.<br/>Reed <small>(R)</small>
| rowspan=3 | Noah M.<br/>Mason <small>(R)</small>
| rowspan=3 | Leo E.<br/>Allen<br/><small>(R)</small>
| rowspan=3 | Harold H.<br/>Velde <small>(R)</small>
| rowspan=3 | Robert B.<br/>Chiperfield<br/><small>(R)</small>
| rowspan=3 | Peter F.<br/>Mack Jr.<br/><small>(D)</small>
| rowspan=2 | Rolla C.<br/>McMillen <small>(R)</small>
| rowspan=3 | Edward<br/>H.<br/>Jenison<br/><small>(R)</small>
| rowspan=3 | Charles W.<br/>Vursell <small>(R)</small>
| rowspan=3 | Melvin<br/>Price<br/><small>(D)</small>
!
| rowspan=2 | 81st<br/>(1949–1951)
|- style="height:2em"
| rowspan=2 | C. W.<br/>Bishop <small>(R)</small>
|- style="height:2em"
| | Richard B.<br/>Vail <small>(R)</small>
| | Fred E.<br/>Busbey <small>(R)</small>
| | William E.<br/>McVey <small>(R)</small>
| | John C.<br/>Kluczynski <small>(D)</small>
| | Timothy P.<br/>Sheehan <small>(R)</small>
| | Marguerite<br/>Church <small>(R)</small>
| | William L.<br/>Springer <small>(R)</small>
| 82nd<br/>(1951–1953)
|}
</div>
1953–1963: 25 seats
Following the 1950 census, Illinois was apportioned 25 seats, all of which were elected from single-member districts.
{| class="wikitable" style="float:left; margin:0; margin-right:-0.5px; margin-top:14px; text-align:center;"
|- style="white-space:nowrap; height:4.1em;"
! Congress
|- style="white-space:nowrap; height:3em;"
|<br/>(1953–1955)
|- style="white-space:nowrap; height:3em"
| <br/>(1955–1957)
|- style="white-space:nowrap; height:3em"
|<br/>(1957–1959)
|- style="white-space:nowrap; height:3em"
|<br/>(1959–1961)
|- style="white-space:nowrap; height:3em"
|<br/>(1961–1963)
|}
<div style="overflow-x:auto; white-space:nowrap;">
{| class=wikitable style="text-align:center"
! colspan=10 | District
! colspan=10 | District
! colspan=5 | District
! rowspan=2 | Cong­ress
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em" style="height:2em"
| rowspan=6 | William<br/>L.<br/>Dawson<br/><small>(D)</small>
| rowspan=6 | Barratt<br/>O'Hara<br/><small>(D)</small>
| | Fred E.<br/>Busbey <small>(R)</small>
| rowspan=3 | William<br/>E.<br/>McVey<br/><small>(R)</small>
| rowspan=6 | John C.<br/>Kluczynski<br/><small>(D)</small>
| rowspan=6 | Thomas<br/>J.<br/>O'Brien<br/><small>(D)</small>
| rowspan=3 | James<br/>Bowler<br/><small>(D)</small>
| rowspan=3 | Thomas<br/>S.<br/>Gordon<br/><small>(D)</small>
| rowspan=5 | Sidney<br/>R.<br/>Yates<br/><small>(D)</small>
| rowspan=2 | Richard<br/>W.<br/>Hoffman<br/><small>(R)</small>
| rowspan=3 | Timothy<br/>P.<br/>Sheehan<br/><small>(R)</small>
| | Edgar A.<br/>Jonas <small>(R)</small>
| rowspan=5 | Marguerite<br/>Church <small>(R)</small>
| rowspan=2 | Chauncey<br/>W.<br/>Reed <small>(R)</small>
| rowspan=5 | Noah<br/>M.<br/>Mason<br/><small>(R)</small>
| rowspan=4 | Leo E.<br/>Allen <small>(R)</small>
| rowspan=6 | Leslie<br/>C.<br/>Arends<br/><small>(R)</small>
| rowspan=2 | Harold<br/>H.<br/>Velde<br/><small>(R)</small>
| rowspan=5 | Robert B.<br/>Chiperfield<br/><small>(R)</small>
| rowspan=3 | Sid<br/>Simpson<br/><small>(R)</small>
| rowspan=5 | Peter<br/>F.<br/>Mack<br/>Jr.<br/><small>(D)</small>
| rowspan=6 | William<br/>L.<br/>Springer<br/><small>(R)</small>
| rowspan=3 | Charles<br/>W.<br/>Vursell<br/><small>(R)</small>
| rowspan=6 | Melvin<br/>Price<br/><small>(D)</small>
| | C. W.<br/>Bishop <small>(R)</small>
| 83rd<br/>(1953–1955)
|- style="height:2em" style="height:2em"
| | James C.<br/>Murray <small>(D)</small>
| rowspan=3 | Charles A.<br/>Boyle <small>(D)</small>
| rowspan=4 | Ken<br/>Gray <small>(D)</small>
| 84th<br/>(1955–1957)
|- style="height:2em" style="height:2em"
| | Emmet<br/>Byrne <small>(R)</small>
| rowspan=3 | Harold<br/>R.<br/>Collier<br/><small>(R)</small>
| | Russell W.<br/>Keeney <small>(R)</small>
| rowspan=3 | Bob<br/>Michel<br/><small>(R)</small>
| 85th<br/>(1957–1959)
|- style="height:2em" style="height:2em"
| rowspan=2 | William T.<br/>Murphy<br/><small>(D)</small>
| rowspan=2 | Ed<br/>Derwinski<br/><small>(R)</small>
| rowspan=2 | Roland<br/>V.<br/>Libonati<br/><small>(D)</small>
| rowspan=2 | Dan<br/>Rosten-<br/>kowski<br/><small>(D)</small>
| rowspan=2 | Roman<br/>Pucinski<br/><small>(D)</small>
| rowspan=2 | Elmer J.<br/>Hoffman<br/><small>(R)</small>
| | Edna O.<br/>Simpson <small>(R)</small>
| rowspan=2 | George<br/>E.<br/>Shipley<br/><small>(D)</small>
| 86th<br/>(1959–1961)
|- style="height:2em" style="height:2em"
| | Edward R.<br/>Finnegan <small>(D)</small>
| | John B.<br/>Anderson <small>(R)</small>
| | Paul<br/>Findley <small>(R)</small>
| 87th<br/>(1961–1963)
|}
</div>
1963–1983: 24 seats
Following the 1960 census, Illinois was apportioned 24 seats.
{| class="wikitable" style="float:left; margin:0; margin-right:-0.5px; margin-top:14px; text-align:center;"
|- style="white-space:nowrap; height:4.04em;"
! Congress
|- style="white-space:nowrap; height:3em;"
|<br/>(1963–1965)
|- style="white-space:nowrap; height:3em"
| <br/>(1965–1967)
|- style="white-space:nowrap; height:3em"
|<br/>(1967–1969)
|- style="white-space:nowrap; height:3em"
|<br/>(1969–1971)
|- style="white-space:nowrap; height:3em"
|<br/>(1971–1973)
|- style="white-space:nowrap; height:3em;"
|<br/>(1973–1975)
|- style="white-space:nowrap; height:3em"
| <br/>(1975–1977)
|- style="white-space:nowrap; height:3em"
|<br/>(1977–1979)
|- style="white-space:nowrap; height:3em"
|<br/>(1979–1981)
|- style="white-space:nowrap; height:3em"
|<br/>(1981–1983)
|}
<div style="overflow-x:auto; white-space:nowrap;">
{| class=wikitable style="text-align:center"
! colspan=10 | District
! colspan=10 | District
! colspan=4 | District
! rowspan=2 | Congress
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em" style="height:2em"
| rowspan=4 | William L.<br/>Dawson <small>(D)</small>
| rowspan=3 | Barratt<br/>O'Hara <small>(D)</small>
| rowspan=4 | William T.<br/>Murphy <small>(D)</small>
| rowspan=10 | Ed<br/>Derwinski<br/><small>(R)</small>
| rowspan=7 | John C.<br/>Kluczynski<br/><small>(D)</small>
| | Thomas J.<br/>O'Brien <small>(D)</small>
| | Roland V.<br/>Libonati <small>(D)</small>
| rowspan=10 | Dan<br/>Rosten-<br/>kowski<br/><small>(D)</small>
| | Edward R.<br/>Finnegan <small>(D)</small>
| rowspan=5 | Harold R.<br/>Collier <small>(R)</small>
| rowspan=5 | Roman<br/>Pucinski<br/><small>(D)</small>
| rowspan=5 | Bob<br/>McClory<br/><small>(R)</small>
| rowspan=3 | Donald<br/>Rumsfeld<br/><small>(R)</small>
| | Elmer J.<br/>Hoffman <small>(R)</small>
| rowspan=4 | Charlotte<br/>Thompson<br/>Reid <small>(R)</small>
| rowspan=9 | John B.<br/>Anderson<br/><small>(R)</small>
| rowspan=5 | Leslie<br/>C.<br/>Arends<br/><small>(R)</small>
| rowspan=10 | Bob<br/>Michel<br/><small>(R)</small>
| | Robert T.<br/>McLoskey <small>(R)</small>
| rowspan=10 | Paul<br/>Findley<br/><small>(R)</small>
| rowspan=5 | Ken<br/>Gray<br/><small>(D)</small>
| rowspan=5 | William<br/>L.<br/>Springer<br/><small>(R)</small>
| rowspan=5 | George<br/>E.<br/>Shipley<br/><small>(D)</small>
| rowspan=5 | Melvin<br/>Price <small>(D)</small>
| 88th<br/>(1963–1965)
|- style="height:2em" style="height:2em"
| rowspan=3 | Daniel J.<br/>Ronan <small>(D)</small>
| rowspan=4 | Frank<br/>Annunzio<br/><small>(D)</small>
| rowspan=9 | Sidney R.<br/>Yates <small>(D)</small>
| rowspan=9 | John<br/>Erlenborn<br/><small>(R)</small>
| | Gale<br/>Schisler <small>(D)</small>
| 89th<br/>(1965–1967)
|- style="height:2em" style="height:2em"
| rowspan=8 | Tom<br/>Railsback<br/><small>(R)</small>
| 90th<br/>(1967–1969)
|- style="height:2em" style="height:2em"
| rowspan=2 | Abner<br/>Mikva <small>(D)</small>
| rowspan=2 | Phil<br/>Crane<br/><small>(R)</small>
| 91st<br/>(1969–1971)
|- style="height:2em" style="height:2em"
| rowspan=4 | Ralph<br/>Metcalfe <small>(D)</small>
| | Morgan F.<br/>Murphy <small>(D)</small>
| | George W.<br/>Collins <small>(D)</small>
| | Cliffard D.<br/>Carlson <small>(R)</small>
| 92nd<br/>(1971–1973)
|- style="height:2em" style="height:2em"
| rowspan=4 | Morgan<br/>F.<br/>Murphy<br/><small>(D)</small>
| | Robert P.<br/>Hanrahan <small>(R)</small>
| | Harold R.<br/>Collier <small>(R)</small>
| rowspan=5 | Cardiss<br/>Collins <small>(D)</small>
| | Samuel H.<br/>Young <small>(R)</small>
| rowspan=5 | Frank<br/>Annunzio<br/><small>(D)</small>
| rowspan=5 | Phil<br/>Crane<br/><small>(R)</small>
| rowspan=5 | Bob<br/>McClory<br/><small>(R)</small>
| | Leslie C.<br/>Arends <small>(R)</small>
| rowspan=5 | George<br/>M.<br/>O'Brien<br/><small>(R)</small>
| rowspan=5 | Ed<br/>Madigan<br/><small>(R)</small>
| rowspan=3 | George<br/>E.<br/>Shipley<br/><small>(D)</small>
| rowspan=5 | Melvin<br/>Price<br/><small>(D)</small>
| | Ken<br/>Gray <small>(D)</small>
| 93rd<br/>(1973–1975
|- style="height:2em" style="height:2em"
| rowspan=4 | Marty<br/>Russo <small>(D)</small>
| rowspan=4 | Henry<br/>Hyde <small>(R)</small>
| rowspan=3 | Abner<br/>Mikva <small>(D)</small>
| | Tim Lee<br/>Hall <small>(D)</small>
| rowspan=4 | Paul<br/>Simon<br/><small>(D)</small>
| 94th<br/>(1975–1977)
|- style="height:2em" style="height:2em"
| rowspan=3 | John G.<br/>Fary <small>(D)</small>
| rowspan=3 | Tom<br/>Corcoran<br/><small>(R)</small>
| 95th<br/>(1977–1979)
|- style="height:2em" style="height:2em"
| | Bennett<br/>Stewart <small>(D)</small>
| rowspan=2 | Dan<br/>Crane<br/><small>(R)</small>
| 96th<br/>(1979–1981)
|- style="height:2em" style="height:2em"
| | Harold<br/>Washington <small>(D)</small>
| | Gus<br/>Savage <small>(D)</small>
| | John<br/>Porter <small>(R)</small>
| | Lynn M.<br/>Martin <small>(R)</small>
| 97th<br/>(1981–1983)
|}
</div>
1983–1993: 22 seats
Following the 1980 census, Illinois was apportioned 22 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Cong­ress
! colspan=22 | District
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em" style="height:2em"
| 98th<br/>(1983–1985)
| | Harold<br/>Washing­ton <small>(D)</small>
| rowspan=5 | Gus<br/>Savage<br/><small>(D)</small>
| rowspan=5 | Marty<br/>Russo<br/><small>(D)</small>
| rowspan=2 | George M.<br/>O'Brien <small>(R)</small>
| rowspan=5 | Bill<br/>Lipinski<br/><small>(D)</small>
| rowspan=5 | Henry<br/>Hyde<br/><small>(R)</small>
| rowspan=5 | Cardiss<br/>Collins<br/><small>(D)</small>
| rowspan=5 | Dan<br/>Rosten­kowski<br/><small>(D)</small>
| rowspan=5 | Sidney<br/>Yates <small>(D)</small>
| rowspan=5 | John<br/>Porter<br/><small>(R)</small>
| rowspan=5 | Frank<br/>Annunzio<br/><small>(D)</small>
| rowspan=5 | Phil<br/>Crane<br/><small>(R)</small>
| | John<br/>Erlen­born <small>(R)</small>
| | Tom<br/>Corcoran <small>(R)</small>
| rowspan=5 | Ed<br/>Madigan<br/><small>(R)</small>
| rowspan=4 | Lynn M.<br/>Martin<br/><small>(R)</small>
| rowspan=5 | Lane<br/>Evans<br/><small>(D)</small>
| rowspan=5 | Bob<br/>Michel<br/><small>(R)</small>
| | Dan<br/>Crane <small>(R)</small>
| rowspan=5 | Dick<br/>Durbin<br/><small>(D)</small>
| rowspan=3 | Melvin<br/>Price<br/><small>(D)</small>
| | Paul<br/>Simon <small>(D)</small>
|- style="height:2em" style="height:2em"
| 99th<br/>(1985–1987)
| rowspan=4 | Charles<br/>Hayes<br/><small>(D)</small>
| rowspan=4 | Harris<br/>Fawell<br/><small>(R)</small>
| | John E.<br/>Grotberg <small>(R)</small>
| rowspan=4 | Terry L.<br/>Bruce<br/><small>(D)</small>
| rowspan=2 | Ken<br/>Gray<br/><small>(D)</small>
|- style="height:2em" style="height:2em"
| 100th<br/>(1987–1989)
| | Jack<br/>Davis <small>(R)</small>
| rowspan=3 | Dennis<br/>Hastert<br/><small>(R)</small>
|- style="height:2em" style="height:2em"
| 101st<br/>(1989–1991)
| rowspan=2 | George<br/>Sang­meister<br/><small>(D)</small>
| rowspan=2 | Jerry<br/>Costello<br/><small>(D)</small>
| rowspan=2 | Glenn<br/>Poshard<br/><small>(D)</small>
|- style="height:2em" style="height:2em"
| 102nd<br/>(1991–1993)
| | John<br/>Cox <small>(D)</small>
|}
1993–2003: 20 seats
Following the 1990 census, Illinois was apportioned 20 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Cong­ress
! colspan=20 | District
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2em" style="height:2em"
| 103rd<br/>(1993–1995)
| rowspan=5 | Bobby<br/>Rush<br/><small>(D)</small>
| rowspan=2 | Mel<br/>Reynolds<br/><small>(D)</small>
| rowspan=5 | Bill<br/>Lipinski<br/><small>(D)</small>
| rowspan=5 | Luis<br/>Gutiérrez<br/><small>(D)</small>
| | Dan<br/>Rosten­kowski <small>(D)</small>
| rowspan=5 | Henry<br/>Hyde<br/><small>(R)</small>
| rowspan=2 | Cardiss<br/>Collins<br/><small>(D)</small>
| rowspan=5 | Phil<br/>Crane<br/><small>(R)</small>
| rowspan=3 | Sidney<br/>Yates<br/><small>(D)</small>
| rowspan=4 | John<br/>Porter<br/><small>(R)</small>
| | George<br/>Sang­meister <small>(D)</small>
| rowspan=5 | Jerry<br/>Costello<br/><small>(D)</small>
| rowspan=3 | Harris<br/>Fawell<br/><small>(R)</small>
| rowspan=5 | Dennis<br/>Hastert<br/><small>(R)</small>
| rowspan=4 | Tom<br/>Ewing<br/><small>(R)</small>
| rowspan=5 | Don<br/>Manzullo<br/><small>(R)</small>
| rowspan=5 | Lane<br/>Evans<br/><small>(D)</small>
| | Bob<br/>Michel <small>(R)</small>
| rowspan=3 | Glenn<br/>Poshard<br/><small>(D)</small>
| rowspan=2 | Dick<br/>Durbin<br/><small>(D)</small>
|- style="height:2em" style="height:2em"
| 104th<br/>(1995–1997)
| | Michael<br/>Flanagan <small>(R)</small>
| rowspan=4 | Jerry<br/>Weller<br/><small>(R)</small>
| rowspan=4 | Ray<br/>LaHood<br/><small>(R)</small>
|- style="height:2em" style="height:2em"
| 105th<br/>(1997–1999)
| rowspan=3 | Jesse<br/>Jackson<br/>Jr. <small>(D)</small>
| rowspan=3 | Rod<br/>Blago­jevich<br/><small>(D)</small>
| rowspan=3 | Danny<br/>Davis<br/><small>(D)</small>
| rowspan=3 | John<br/>Shimkus<br/><small>(R)</small>
|- style="height:2em" style="height:2em"
| 106th<br/>(1999–2001)
| rowspan=2 | Jan<br/>Schakow­sky<br/><small>(D)</small>
| rowspan=2 | Judy<br/>Biggert<br/><small>(R)</small>
| rowspan=2 | David<br/>Phelps<br/><small>(D)</small>
|- style="height:2em" style="height:2em"
| 107th<br/>(2001–2003)
| | Mark<br/>Kirk <small>(R)</small>
| | Tim<br/>Johnson <small>(R)</small>
|}
2003–2013: 19 seats
Following the 2000 census, Illinois was apportioned 19 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Congress
! colspan=19 | District
|- style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2.5em"
| 108th
| rowspan=5 | Bobby<br/>Rush<br/><small>(D)</small>
| rowspan=5 | Jesse<br/>Jackson<br/>Jr. <small>(D)</small>
| | Bill<br/>Lipinski <small>(D)</small>
| rowspan=5 | Luis<br/>Gutiérrez<br/><small>(D)</small>
| rowspan=3 | Rahm<br/>Emanuel<br/><small>(D)</small>
| rowspan=2 | Henry<br/>Hyde<br/><small>(R)</small>
| rowspan=5 | Danny<br/>Davis<br/><small>(D)</small>
| | Phil<br/>Crane <small>(R)</small>
| rowspan=5 | Jan<br/>Schakowsky<br/><small>(D)</small>
| rowspan=4 | Mark<br/>Kirk<br/><small>(R)</small>
| rowspan=3 | Jerry<br/>Weller<br/><small>(R)</small>
| rowspan=5 | Jerry<br/>Costello<br/><small>(D)</small>
| rowspan=5 | Judy<br/>Biggert<br/><small>(R)</small>
| rowspan=3 | Dennis<br/>Hastert<br/><small>(R)</small>
| rowspan=5 | Tim<br/>Johnson<br/><small>(R)</small>
| rowspan=5 | Don<br/>Manzullo<br/><small>(R)</small>
| rowspan=2 | Lane<br/>Evans <small>(D)</small>
| rowspan=3 | Ray<br/>LaHood<br/><small>(R)</small>
| rowspan=5 | John<br/>Shimkus<br/><small>(R)</small>
|- style="height:2.5em"
| 109th
| rowspan=4 | Dan<br/>Lipinski<br/><small>(D)</small>
| rowspan=3 | Melissa<br/>Bean <small>(D)</small>
|- style="height:2.5em"
| 110th
| rowspan=3 | Peter<br/>Roskam<br/><small>(R)</small>
| rowspan=2 | Phil<br/>Hare <small>(D)</small>
|- style="height:2.5em"
| 111th
| rowspan=2 | Mike<br/>Quigley<br/><small>(D)</small>
| | Debbie<br/>Halvorson <small>(D)</small>
| | Bill<br/>Foster <small>(D)</small>
| rowspan=2 | Aaron<br/>Schock<br/><small>(R)</small>
|- style="height:2.5em"
| 112th
| | Joe<br/>Walsh <small>(R)</small>
| | Bob<br/>Dold <small>(R)</small>
| | Adam<br/>Kinzinger <small>(R)</small>
| | Randy<br/>Hultgren <small>(R)</small>
| | Bobby<br/>Schilling <small>(R)</small>
|}
2013–2023: 18 seats
Following the 2010 census, Illinois was apportioned 18 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Congress
! colspan=18 | District
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2.5em"
| 113th
| rowspan=6 | Bobby<br/>Rush<br/><small>(D)</small>
| rowspan=6 | Robin<br/>Kelly<br/><small>(D)</small>
| rowspan=5 | Dan<br/>Lipinski<br/><small>(D)</small>
| rowspan=4 | Luis<br/>Gutiérrez<br/><small>(D)</small>
| rowspan=6 | Mike<br/>Quigley<br/><small>(D)</small>
| rowspan=4 | Peter<br/>Roskam<br/><small>(R)</small>
| rowspan=6 | Danny<br/>Davis<br/><small>(D)</small>
| rowspan=3 | Tammy<br/>Duck­worth<br/><small>(D)</small>
| rowspan=6 | Jan<br/>Schakow­sky<br/><small>(D)</small>
| | Brad<br/>Schneider <small>(D)</small>
| rowspan=6 | Bill<br/>Foster<br/><small>(D)</small>
| | William<br/>Enyart <small>(D)</small>
| rowspan=6 | Rodney<br/>Davis<br/><small>(R)</small>
| rowspan=4 | Randy<br/>Hultgren<br/><small>(R)</small>
| rowspan=5 | John<br/>Shimkus<br/><small>(R)</small>
| rowspan=6 | Adam<br/>Kinzinger<br/><small>(R)</small>
| rowspan=6 | Cheri<br/>Bustos<br/><small>(D)</small>
| rowspan=2 | Aaron<br/>Schock<br/><small>(R)</small>
|- style="height:1.5em"
| rowspan=2 | 114th
| rowspan=2 | Bob<br/>Dold <small>(R)</small>
| rowspan=5 | Mike<br/>Bost <small>(R)</small>
|- style="height:1.5em"
| rowspan=4 | Darin<br/>LaHood<br/><small>(R)</small>
|- style="height:2.5em"
| 115th
| rowspan=3 | Raja<br/>Krishna­moorthi<br/><small>(D)</small>
| rowspan=3 | Brad<br/>Schneider<br/><small>(D)</small>
|- style="height:2.5em"
| 116th
| rowspan=2 | Chuy<br/>García<br/><small>(D)</small>
| rowspan=2 | Sean<br/>Casten<br/><small>(D)</small>
| rowspan=2 | Lauren<br/>Under­wood<br/><small>(D)</small>
|- style="height:2.5em"
| 117th
| | Marie<br/>Newman <small>(D)</small>
| | Mary<br/>Miller <small>(R)</small>
|}
2023–present: 17 seats
Following the 2020 census, Illinois was apportioned 17 seats.
{| class=wikitable style="text-align:center"
! rowspan=2 | Congress
! colspan=17 | District
|- style="height:2em" style="height:2em"
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
|- style="height:2.5em"
| 118th
| rowspan=2| Jonathan<br/>Jackson<br/><small>(D)</small>
| rowspan=2| Robin<br/>Kelly<br/><small>(D)</small>
| rowspan=2| Delia<br/>Ramirez<br/><small>(D)</small>
| rowspan=2| Chuy<br/>García<br/><small>(D)</small>
| rowspan=2| Mike<br/>Quigley<br/><small>(D)</small>
| rowspan=2| Sean<br/>Casten<br/><small>(D)</small>
| rowspan=2| Danny<br/>Davis<br/><small>(D)</small>
| rowspan=2| Raja<br/>Krishnamoorthi<br/><small>(D)</small>
| rowspan=2| Jan<br/>Schakow­sky<br/><small>(D)</small>
| rowspan=2| Brad<br/>Schneider<br/><small>(D)</small>
| rowspan=2| Bill<br/>Foster<br/><small>(D)</small>
| rowspan=2| Mike<br/>Bost<br/><small>(R)</small>
| rowspan=2| Nikki<br/>Budzinski<br/><small>(D)</small>
| rowspan=2| Lauren<br/>Underwood<br/><small>(D)</small>
| rowspan=2| Mary<br/>Miller<br/><small>(R)</small>
| rowspan=2| Darin<br/>LaHood<br/><small>(R)</small>
| rowspan=2| Eric<br/>Sorensen<br/><small>(D)</small>
|- style="height:2.5em"
| 119th
|}
Key
See also
- List of United States congressional districts
- Illinois's congressional districts
- Political party strength in Illinois