The 2026 elections put all 17 of Illinois’s U.S. House seats on the ballot on November 3, 2026, alongside about a third of the U.S. Senate. House members serve two-year terms, so every district is contested in each even-numbered year. Illinois’s House delegation is currently 3 Republicans and 14 Democrats.
The 2026 district map
Illinois’s 17 congressional districts use the same lines as in 2024, so the 2026 races run on those boundaries. Each district holds about 761,000 people, the average set by the 2020 census when House seats were reapportioned among the states. Statewide, Illinois voted for Kamala Harris by about 11 points in 2024, which sets the backdrop for its district races. How that statewide vote turns into seats depends on where the lines fall, which is why the map is contested as often as the candidates. Illinois also elects two U.S. Senators, currently Dick Durbin (D) and Tammy Duckworth (D). Senate terms run six years and the state’s two seats sit on different cycles. One of the two seats is up in 2026. Because the U.S. House is closely divided between the two parties, results in the most competitive districts, in Illinois and elsewhere, can help decide which party controls the chamber for the next two years.
After the 2020 Census, Illinois lost a seat in reapportionment, leaving it with 17 districts for the decade. The current map, drawn after that census, sets the district boundaries for the 2026 races and holds through 2030 unless a court or the legislature orders new lines.
Races to Watch
A few of Illinois’s districts were closer than the rest at the top of the ticket in 2024, and they are the seats most worth watching in 2026. District 17 voted for Kamala Harris by about 5 points in 2024, the closest result in the state. District 14 voted for Kamala Harris by about 5 points in 2024. District 6 voted for Kamala Harris by about 6 points in 2024. These are the districts both parties tend to spend on, while Illinois’s remaining seats were drawn with clearer partisan majorities and were decided by wider margins, so they start the cycle favoring one side.
Key Dates for Illinois Voters
Illinois holds its statewide primary on March 17, 2026. The primary decides each party’s nominees for the U.S. House, U.S. Senate, and other offices, and the winners advance to the general election for all 17 House seats and the Senate seat on November 3, 2026. That general election falls on the same day across the country, and the results help set the makeup of the next Congress, which is seated in January 2027. Registration deadlines, mail-ballot rules, and early-voting dates are set by the state and can change, so confirm them with the Illinois state election office before you plan to vote.
Find Your Illinois District
Not sure which district you are in? Use the ZIP code lookup on our home page to find your Illinois congressional district and see who represents you. For maps and the full list of the state’s seats, see the Illinois congressional districts hub. For the Senate picture in every state, see U.S. Senators by State.
See also: 2026 Congressional Elections and U.S. Senators by State.
