Illinois has 17 congressional districts, each covering roughly 753,677 residents based on the 2020 Census. The state dropped from 18 seats to 17 after that count because its population shrank by about 44,000 while other states grew faster.1U.S. Census Bureau. Table D1 and D2 – Number of Seats Gained and Lost in U.S. House of Representatives by State The Illinois General Assembly draws the boundaries as ordinary legislation, and the current map has been in effect since the 2022 elections.
How to Find Your District
The most reliable lookup is the Illinois State Board of Elections District Locator. Enter your home address and it returns your congressional district number along with your representative’s name and contact information.
The U.S. House of Representatives also offers a lookup at house.gov, but it only takes a zip code.2U.S. House of Representatives. Find Your Representative A single zip code can straddle two or more districts, so the House tool sometimes returns multiple possible representatives. The SBE tool, which uses your full street address, is more precise.
What the 17 Districts Look Like
Most of the districts are packed into the northeastern corner of the state. Chicago proper is divided among several districts, and more fan out through the collar counties of DuPage, Lake, Kane, Will, and McHenry. A handful stretch across the rest of Illinois, where population density drops off sharply. The 15th District, for example, spans a huge portion of eastern and southeastern Illinois to reach the 753,677-person target.
In the 119th Congress (2025–2027), the delegation stands at 14 Democrats and 3 Republicans. The three Republican-held seats cover large portions of rural and exurban central and southern Illinois. One district is considered remotely competitive in a typical election cycle.
Who Draws the Map
Illinois gives its state legislature full control over congressional boundaries. After the Census Bureau releases new population data every ten years, the General Assembly drafts a new map and passes it through both chambers like any other bill. The governor can sign or veto it.3All About Redistricting. Illinois
For the current cycle, the legislature passed the new map in November 2021 and Governor J.B. Pritzker signed it into law later that month. The 17-district map took effect with the 2022 elections and remains active.3All About Redistricting. Illinois No court has struck down the current congressional map.
The practical consequence of this arrangement is that whichever party controls both the General Assembly and the governor’s office controls the map for the decade.
Legal Rules the Map Has to Follow
Two federal requirements govern any Illinois congressional map.
The first is population equality. The Supreme Court held in Wesberry v. Sanders that Article I, Section 2 of the Constitution requires congressional districts to be as nearly equal in population as practicable, so that one person’s vote carries roughly the same weight as another’s.4Justia. Wesberry v Sanders, 376 US 1 (1964) Courts scrutinize even tiny population differences between congressional districts far more strictly than they do for state legislative districts.
The second is Section 2 of the Voting Rights Act, which prohibits any voting practice, including redistricting, that leaves minority voters with less opportunity than other voters to participate in elections and elect their preferred candidates.5Office of the Law Revision Counsel. 52 USC 10301 – Denial or Abridgement of Right to Vote on Account of Race or Color In practice, the map must not crack apart or pack together racial or language minority communities in ways that dilute their political power.
One point that often surprises people: the Illinois Constitution requires state legislative districts to be compact and contiguous, but those rules apply only to state House and Senate maps, not to congressional districts.6Illinois General Assembly. Illinois Constitution Article IV – The Legislature – Section 3 Legislative Redistricting Congressional maps in Illinois have no state-level compactness requirement, which gives the legislature significantly more freedom in how it shapes the boundaries.
Gerrymandering Concerns
Illinois is widely regarded as one of the most aggressively gerrymandered states in the country for congressional seats. Princeton University’s Gerrymandering Project has given the map failing grades in partisan fairness, competitiveness, and compactness. The numbers tell the story: in the 2024 presidential election, about 54% of Illinois voters supported the Democratic candidate, yet Democrats hold roughly 82% of the state’s U.S. House seats.
The absence of a state compactness rule for congressional maps makes irregular shapes easier to draw. The only federal check on purely partisan line-drawing is the Supreme Court, which held in Rucho v. Common Cause (2019) that partisan gerrymandering claims are political questions beyond the reach of federal courts. That decision effectively closed the federal courthouse door to challenges based purely on partisan unfairness.
Why Reform Has Stalled
Frustration with legislative control has driven multiple attempts to create an independent commission in Illinois. The most prominent was a 2016 citizen-initiated constitutional amendment that would have established an 11-member redistricting commission selected through a randomized process. Any map would have needed approval from at least seven members, including members of both parties and independents.
The Illinois Supreme Court struck the initiative from the ballot in a 4–3 decision, holding that the proposed changes went beyond the scope of what citizen initiatives may address under the Illinois Constitution. The court found that altering the attorney general’s role in redistricting challenges fell outside the structural and procedural subjects permitted by Article IV’s initiative clause. No comparable reform has cleared the legal hurdles since, and the legislature retains sole authority over the process.
What Happens After the 2030 Census
The current 17-district map will stay in place through the 2030 elections. After the 2030 Census results arrive, Illinois’s population trends will again decide whether the state keeps, gains, or loses seats. Illinois has lost at least one seat after each of the last three census cycles, so another reduction is a real possibility if the state continues losing residents relative to faster-growing states in the South and West.
Whether the General Assembly draws the next map or some future reform shifts that power to an independent body, the same federal requirements will apply: equal population across districts and compliance with the Voting Rights Act.