thumb|upright=1.4|right|alt=refer to caption|Map of Idaho's two congressional districts for the [[United States House of Representatives since 2023]]
Since Idaho became a U.S. state in 1890, it has sent congressional delegations to the United States Senate and United States House of Representatives, beginning with the 51st United States Congress. Prior to 1890, Idaho sent non-voting delegates to the House of Representatives from 1864 to 1889. Each state elects two senators to serve for six years in general elections, with their re-election staggered. Prior to the ratification of the Seventeenth Amendment in 1913, senators were elected by the Idaho Legislature. Each state elects a varying number of, but at least one, Idaho has sent two members to the House in each congressional delegation since the 1910 United States census.
A total of 63 unique individuals have represented Idaho in Congress; Idaho has had 26 senators and 44 representatives, and 7 have served in both the House and the Senate. Two women from Idaho, Gracie Pfost and Helen Chenoweth, have served in the House, while none have served in the Senate. Crapo is the second-longest serving senator in Idaho history, after William Borah.
Current delegation
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|+ Current U.S. senators from Idaho
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! CPVI : Idaho has not elected a Democratic member of Congress since Walt Minnick was elected in 2008; he was defeated by Republican Raúl Labrador two years later in 2010.
As of April 2025, the Cook Partisan Voting Index, a measure of how strongly partisan congressional districts and states are, ranked both Idaho congressional districts and the state as a whole as solidly Republican.
The dean, or longest-serving member of Congress, of the Idaho delegation is currently Mike Crapo, who has been serving in Congress since his election to the House of Representatives in 1992. After serving in the House for three terms, he was elected to the Senate in 1998.