Rock Island County is a county located in the U.S. state of Illinois, bounded on the west by the Mississippi River. According to the 2020 census, it had a population of 144,672. Its county seat is Rock Island; its largest city is neighboring Moline. Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area.
History
thumb|Rock Island County at the time of its creation in 1831
Rock Island County was formed in 1831 out of Jo Daviess County. It was named for Rock Island, an island in the Mississippi River now known as Arsenal Island. The Rock River (which the Sauk and Meskwaki peoples called Sinnissippi, meaning "rocky waters") flows from Whiteside County and points further east and north and joins the Mississippi River at Rock Island. The Sinnissippi Mounds, dating from the Hopewell period and on the National Register of Historic Places are upriver at Sterling in Whiteside County.
Geography
According to the U.S. Census Bureau, the county has a total area of , of which is land and (5.2%) is water.
In recent years, average temperatures in the county seat of Rock Island have ranged from a low of in January to a high of in July, although a record low of was recorded in February 1996 and a record high of was recorded in July 2006. Average monthly precipitation ranged from in January to in June.
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|footnote=U.S. Decennial Census<br />1790-1960 1900-1990<br />1990-2000 2010
| align = right
2020 census
As of the 2020 census, the county had a population of 144,672. The median age was 40.6 years. 22.1% of residents were under the age of 18 and 19.9% of residents were 65 years of age or older. For every 100 females there were 96.8 males, and for every 100 females age 18 and over there were 94.6 males age 18 and over.
The racial makeup of the county was 71.2% White, 11.5% Black or African American, 0.5% American Indian and Alaska Native, 2.8% Asian, <0.1% Native Hawaiian and Pacific Islander, 5.2% from some other race, and 8.8% from two or more races. Hispanic or Latino residents of any race comprised 13.7% of the population.
The 2020 census counted 88.5% of residents living in urban areas and 11.5% living in rural areas.
There were 60,735 households in the county, of which 27.4% had children under the age of 18 living in them. Of all households, 42.1% were married-couple households, 20.6% were households with a male householder and no spouse or partner present, and 30.0% were households with a female householder and no spouse or partner present. About 33.5% of all households were made up of individuals and 14.7% had someone living alone who was 65 years of age or older.
!Pop 1990
!Pop 2000
!Pop 2010
!style="background-color: #ffffb3;" | Pop 2020
!% 1980
!% 1990
!% 2000
!% 2010
!style="background-color: #ffffb3;" |% 2020
|-
|White alone (NH)
|147,393
|128,986
|121,705
|111,764
|style='background: #ffffe6; |97,689
|88.81%
|86.73%
|81.48%
|75.75%
|style='background: #ffffe6; |67.52%
|-
|Black or African American alone (NH)
|9,710
|10,290
|11,099
|12,911
|style='background: #ffffe6; |16,169
|5.85%
|6.92%
|7.43%
|8.75%
|style='background: #ffffe6; |11.18%
|-
|Native American or Alaska Native alone (NH)
|257
|301
|288
|283
|style='background: #ffffe6; |240
|0.15%
|0.20%
|0.19%
|0.19%
|style='background: #ffffe6; |0.17%
|-
|Asian alone (NH)
|889
|980
|1,499
|2,383
|style='background: #ffffe6; |4,033
|0.54%
|0.66%
|1.00%
|1.62%
|style='background: #ffffe6; |2.79%
|-
|Native Hawaiian or Pacific Islander alone (NH)
|x
|x
|34
|44
|style='background: #ffffe6; |35
|x
|x
|0.02%
|0.03%
|style='background: #ffffe6; |0.02%
|-
|Other race alone (NH)
|510
|82
|109
|135
|style='background: #ffffe6; |482
|0.31%
|0.06%
|0.07%
|0.09%
|style='background: #ffffe6; |0.33%
|-
|Mixed race or Multiracial (NH)
|x
|x
|1,849
|2,908
|style='background: #ffffe6; |6,182
|x
|x
|1.24%
|1.97%
|style='background: #ffffe6; |4.27%
|-
|Hispanic or Latino (any race)
|7,209
|8,084
|12,791
|17,118
|style='background: #ffffe6; |19,842
|4.34%
|5.44%
|8.56%
|11.60%
|style='background: #ffffe6; |13.72%
|-
|Total
|165,968
|148,723
|149,374
|147,546
|style='background: #ffffe6; |144,672
|100.00%
|100.00%
|100.00%
|100.00%
|style='background: #ffffe6; |100.00%
|}
Racial / Ethnic Profile of places in Rock Island County, Illinois (2020 census)
{| class="toccolours collapsible collapsed" width=50% align="left"
|-
! style="background:#F5DEB3"| <small>Racial / Ethnic Profile of places in Rock Island County, Illinois (2020 Census)</small>
|-
|Following is a table of towns and census designated places in Rock Island County, Illinois. Data for the United States (with and without Puerto Rico), the state of Illinois, and Rock Island County itself have been included for comparison purposes.<br> The majority racial/ethnic group is coded per the key below. Communities that extend into and adjacent county or counties are delineated with a followed by an accompanying explanatory note. The full population of each community has been tabulated including the population in adjacent counties.
{| class="wikitable"
|style="background-color:#AAF0D1; width:1em"|
|Majority minority with no dominant group
|-
|style="background-color:#FFFF9F; width:1em"|
|Majority White
|-
|style="background-color:#87CEFA; width:1em"|
|Majority Black
|-
|style="background-color:#FFBD88; widmth:1em"|
|Majority Hispanic
|-
|style="background-color:#E0B0FF; width:1em"|
|Majority Asian
|}
{| class="wikitable sortable" style="text-align:center;"
|+Racial and ethnic composition of places in Rock Island County, Illinois (2020 Census)<br> (NH = Non-Hispanic)<br><small></small>
!Place
!Designation
!Total Population
!White alone (NH)
!%
!Black or<br> African American alone (NH)
!%
!Native American or <br> Alaska Native alone (NH)
!%
!Asian alone (NH)
!%
!Pacific Islander alone (NH)
!%
!Other race alone (NH)
!%
!Mixed race or<br> Multiracial (NH)
!%
!Hispanic or Latino<br> (any race)
!%
|-
|- style="background:#e6f3ff"
|United States of America<br> <small>(50 states and D.C.)</small>
| x
|331,449,281
|191,697,647
|57.84%
|39,940,338
|12.05%
|2,251,699
|0.68%
|19,618,719
|5.92%
|622,018
|0.19%
|1,689,833
|0.51%
|13,548,983
|4.09%
|62,080,044
|18.73%
|-
|- style="background:#e6f3ff"
|<br><small> </small>
| State
| 12,812,508
| 7,472,751
| 58.32%
| 1,775,612
| 13.86%
| 16,561
| 0.13%
| 747,280
| 5.83%
| 2,959
| 0.02%
| 45,080
| 0.35%
| 414,855
| 3.24%
| 2,337,410
| 18.24%
|-
|- style="background:#e6f3ff"
|
| City
| 21,374
| 11,643
| 54.47%
| 3,776
| 17.67%
| 29
| 0.14%
| 787
| 3.68%
| 0
| 0.00%
| 60
| 0.28%
| 816
| 3.82%
| 4,263
| 19.94%
|-
| style="background-color:#FFFF9F; width:1em"| Moline
| City
| 42,985
| 28,038
| 65.23%
| 3,661
| 8.52%
| 75
| 0.17%
| 1,276
| 2.97%
| 13
| 0.03%
| 132
| 0.31%
| 1,759
| 4.09%
| 8,031
| 18.68%
|-
| style="background-color:#FFFF9F; width:1em"| Rock Island
| City
| 37,108
| 21,910
| 59.04%
| 7,135
| 19.23%
| 63
| 0.17%
| 1,603
| 4.32%
| 12
| 0.03%
| 160
| 0.43%
| 1,928
| 5.20%
| 4,297
| 11.58%
|-
| style="background-color:#FFFF9F; width:1em"| Silvis
| City
| 8,003
| 5,366
| 67.05%
| 731
| 9.13%
| 20
| 0.25%
| 174
| 2.17%
| 1
| 0.01%
| 25
| 0.31%
| 332
| 4.15%
| 1,354
| 16.92%
|-
| style="background-color:#FFFF9F; width:1em"| Andalusia
| Village
| 1,184
| 1,099
| 92.82%
| 11
| 0.93%
| 5
| 0.42%
| 1
| 0.08%
| 0
| 0.00%
| 2
| 0.17%
| 30
| 2.53%
| 36
| 3.04%
|-
| style="background-color:#FFFF9F; width:1em"| Carbon Cliff
| Village
| 1,846
| 1,204
| 65.22%
| 299
| 16.20%
| 6
| 0.33%
| 11
| 0.60%
| 2
| 0.11%
| 7
| 0.38%
| 92
| 4.98%
| 225
| 12.19%
|-
| style="background-color:#FFFF9F; width:1em"| Coal Valley
| Village
| 3,873
| 3,411
| 88.07%
| 35
| 0.90%
| 4
| 0.10%
| 30
| 0.77%
| 2
| 0.05%
| 8
| 0.21%
| 137
| 3.54%
| 246
| 6.35%
|-
| style="background-color:#FFFF9F; width:1em"| Cordova
| Village
| 671
| 622
| 92.70%
| 4
| 0.60%
| 2
| 0.30%
| 0
| 0.00%
| 0
| 0.00%
| 5
| 0.75%
| 16
| 2.38%
| 22
| 3.28%
|-
| style="background-color:#FFFF9F; width:1em"| Hampton
| Village
| 1,779
| 1,511
| 84.94%
| 25
| 1.41%
| 2
| 0.11%
| 5
| 0.28%
| 0
| 0.00%
| 13
| 0.73%
| 77
| 4.33%
| 146
| 8.21%
|-
| style="background-color:#FFFF9F; width:1em"| Hillsdale
| Village
| 417
| 384
| 92.09%
| 1
| 0.24%
| 1
| 0.24%
| 0
| 0.00%
| 0
| 0.00%
| 2
| 0.48%
| 16
| 3.84%
| 13
| 3.12%
|-
| style="background-color:#FFFF9F; width:1em"| Milan
| Village
| 5,097
| 4,130
| 81.03%
| 289
| 5.67%
| 13
| 0.26%
| 55
| 1.08%
| 2
| 0.04%
| 20
| 0.39%
| 273
| 5.36%
| 315
| 6.18%
|-
| style="background-color:#FFFF9F; width:1em"| Oak Grove
| Village
| 476
| 414
| 86.97%
| 0
| 0.00%
| 0
| 0.00%
| 5
| 1.05%
| 1
| 0.21%
| 0
| 0.00%
| 22
| 4.62%
| 34
| 7.14%
|-
| style="background-color:#FFFF9F; width:1em"| Port Byron
| Village
| 1,668
| 1,506
| 90.29%
| 10
| 0.60%
| 2
| 0.12%
| 7
| 0.42%
| 0
| 0.00%
| 10
| 0.60%
| 48
| 2.88%
| 85
| 5.10%
|-
| style="background-color:#FFFF9F; width:1em"| Rapids City
| Village
| 964
| 889
| 92.22%
| 8
| 0.83%
| 1
| 0.10%
| 1
| 0.10%
| 0
| 0.00%
| 1
| 0.10%
| 27
| 2.80%
| 37
| 3.84%
|-
| style="background-color:#FFFF9F; width:1em"| Reynolds
| Village
| 498
| 467
| 93.78%
| 2
| 0.40%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 1
| 0.20%
| 20
| 4.02%
| 8
| 1.61%
|-
| style="background-color:#FFFF9F; width:1em"| Barstow
| CDP
| 89
| 83
| 93.26%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 1
| 1.12%
| 1
| 1.12%
| 4
| 4.49%
|-
| style="background-color:#FFFF9F; width:1em"| Buffalo Prairie
| CDP
| 64
| 57
| 89.06%
| 0
| 0.00%
| 0
| 0.00%
| 1
| 1.56%
| 0
| 0.00%
| 0
| 0.00%
| 5
| 7.81%
| 1
| 1.56%
|-
| style="background-color:#FFFF9F; width:1em"| Campbell's Island
| CDP
| 275
| 247
| 89.82%
| 1
| 0.36%
| 1
| 0.36%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 8
| 2.91%
| 18
| 6.55%
|-
| style="background-color:#FFFF9F; width:1em"| Coyne Center
| CDP
| 877
| 784
| 89.40%
| 13
| 1.48%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 53
| 6.04%
| 27
| 3.08%
|-
| style="background-color:#FFFF9F; width:1em"| Edgington
| CDP
| 391
| 374
| 95.65%
| 1
| 0.26%
| 2
| 0.51%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 2
| 0.51%
| 12
| 3.07%
|-
| style="background-color:#FFFF9F; width:1em"| Illinois City
| CDP
| 159
| 144
| 90.57%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 5
| 3.14%
| 10
| 6.29%
|-
| style="background-color:#FFFF9F; width:1em"| Joslin
| CDP
| 85
| 81
| 95.29%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 3
| 3.53%
| 1
| 1.18%
|-
| style="background-color:#FFFF9F; width:1em"| Rock Island Arsenal
| CDP
| 182
| 101
| 55.49%
| 24
| 13.19%
| 0
| 0.00%
| 9
| 4.95%
| 0
| 0.00%
| 6
| 3.30%
| 26
| 14.29%
| 16
| 8.79%
|-
| style="background-color:#FFFF9F; width:1em"| Taylor Ridge
| CDP
| 141
| 127
| 90.07%
| 0
| 0.00%
| 1
| 0.71%
| 0
| 0.00%
| 0
| 0.00%
| 0
| 0.00%
| 8
| 5.67%
| 5
| 3.55%
|-
|}
|}
2010 census
As of the 2010 United States census, there were 147,546 people, 61,303 households, and 38,384 families residing in the county. The population density was . There were 65,756 housing units at an average density of . The racial makeup of the county was 81.6% white, 9.0% black or African American, 1.6% Asian, 0.3% American Indian, 4.4% from other races, and 3.0% from two or more races. Those of Hispanic or Latino origin made up 11.6% of the population.
Of the 61,303 households, 29.0% had children under the age of 18 living with them, 45.3% were married couples living together, 12.7% had a female householder with no husband present, 37.4% were non-families, and 31.6% of all households were made up of individuals. The average household size was 2.34 and the average family size was 2.93. The median age was 40.0 years.
Economy
At one time Mississippi Valley Airlines had its headquarters in Quad City Airport in the county.
John Deere is headquartered in Moline.
Communities
Cities
- East Moline
- Moline
- Rock Island
- Silvis
Villages
- Andalusia
- Carbon Cliff
- Coal Valley (part)
- Cordova
- Hampton
- Hillsdale
- Milan
- Oak Grove
- Port Byron
- Rapids City
- Reynolds (part)
Census-designated places
- Barstow
- Buffalo Prairie
- Campbell's Island
- Coyne Center
- Edgington
- Illinois City
- Joslin
- Rock Island Arsenal
- Taylor Ridge
Townships
Rock Island County is divided into eighteen townships:
- Andalusia
- Blackhawk
- Bowling
- Buffalo Prairie
- Canoe Creek
- Coal Valley
- Coe
- Cordova
- Drury
- Edgington
- Hampton
- Moline
- Port Byron
- Rock Island
- Rural
- South Moline
- South Rock Island
- Zuma
Forts
- Fort Armstrong
Politics
Before 1932, Rock Island County was a Republican stronghold in presidential elections, backing the party's candidate in every election from 1892 to 1928. From 1932 on, it has consistently backed Democratic Party presidential candidates, except for the national Republican landslides of 1952, 1956, 1972, and 1980. In 2016, Donald Trump managed to keep Hillary Clinton to a single-digit margin of victory, the first Republican to do so since Ronald Reagan in 1984; in 2020, Joe Biden increased the Democratic margin from 8.3% to 12.1%. Due to the dominance of the Democratic Party in county politics, Rock Island County remains one of the most Democratic counties outside of the Chicago area in Illinois. Since 2010 the Republican Party began making inroads in county politics, gaining a few seats on the Democratic-dominated county board; however, since 2018, the Republican Party influence on the board has begun to decrease as the county resumed heavy Democratic voting.
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Education
K-12 school districts include:
- Erie Community Unit School District 1
- Mercer County School District 404
- Moline-Coal Valley School District 40
- Orion Community Unit School District 223
- Riverdale Community Unit School District 100
- Rock Island–Milan School District 41
- Rockridge Community Unit School District 300
- Sherrard Community Unit School District 200
There is one secondary school district: United Township High School District 30.
