The Illinois state district map divides the state into 59 Senate districts and 118 House districts, and you can find yours by entering your home address in the Illinois State Board of Elections district locator.1Illinois State Board of Elections. Find My Elected Officials The tool returns your state Senate district, your state House district, and your congressional district, along with the names of the people currently holding each seat.
Look Up Your District by Address
The State Board of Elections locator is the fastest way to see which state legislative districts you live in. Type in your address and the results show your senator and representative in Springfield as well as your U.S. House member. If something looks off, or if you have recently moved, the Board points residents to their local election authority, meaning the county clerk or Board of Election Commissioners, which has the final say on where an address falls.
If you want to see the actual boundaries rather than just a list of names, the Illinois Department of Transportation publishes downloadable statewide maps showing both Senate and House districts. The Illinois General Assembly website carries similar lookup tools plus contact details for every sitting legislator. All of these resources reflect the maps signed into law in September 2021, which govern elections for the rest of the decade.
How Illinois Legislative Districts Are Organized
The Illinois Constitution sets up a nested system. The state is split into 59 Legislative Districts, each with one state senator. Every Senate district is then divided into exactly two Representative Districts, producing 118 House seats.2Illinois General Assembly. Illinois Constitution Article IV – The Legislature Because of that nesting, your House district always sits entirely inside your Senate district, and every resident has one state senator and one state representative.
Based on the 2020 census, each Senate district covers roughly 217,000 residents and each House district roughly 109,000. Those figures are targets rather than fixed numbers. Districts in dense parts of Chicago can be geographically small, while rural districts downstate may sprawl across several counties to reach the same population.
State Districts Are Not the Same as Congressional Districts
People often mix up state legislative districts with congressional districts, but they operate at different levels of government. Illinois currently has 17 seats in the U.S. House, each drawn as its own congressional district. Those lines are separate from the 59 Senate and 118 House districts used for the state legislature. Congressional maps send members to Washington; state legislative maps determine who serves in Springfield. Both are redrawn after each census, but they follow different rules and go through separate approval processes.
Which Map You’re On Right Now
The maps in use today took effect in September 2021 after an unusually rocky drafting process. Because 2020 census data was delayed by the pandemic, lawmakers first passed maps in June 2021 using American Community Survey estimates. A federal three-judge panel found those maps unconstitutionally malapportioned because they were not based on actual census figures and blocked elections under them. Governor Pritzker then signed a revised set of maps on September 24, 2021, drawn from the official 2020 census count.3State of Illinois. Gov. Pritzker Signs Revised Legislative Maps that Preserve Minority Representation The revised maps drew further legal challenges alleging dilution of Latino voting strength and improper use of race in map design, but they remained in effect and will govern elections through the 2030 cycle.
The Rules Behind the Lines
Two layers of law shape any Illinois map: the state constitution and federal voting rights law.
Compact, Contiguous, Equal in Population
Article IV, Section 3 of the Illinois Constitution requires every legislative district to be compact, contiguous, and substantially equal in population.4Illinois General Assembly. Illinois Constitution Article IV – The Legislature – Section 3 Contiguous means every part of the district physically connects; you could travel from one end to the other without leaving it. Compact means the shape shouldn’t snake or stretch across the state in odd patterns. Substantial population equality reflects the one person, one vote principle: if one district holds twice the people of another, its residents effectively have half the voting power.
Courts have generally treated a total population deviation of 10 percent or less between the largest and smallest state legislative districts as presumptively acceptable. That is not a safe harbor. A map under 10 percent can still fall if the variation lacks a legitimate reason, and a map slightly above can survive if the state can explain why.
The Voting Rights Act
Section 2 of the Voting Rights Act prohibits any voting practice that results in minority voters having less opportunity to elect representatives of their choice.5Office of the Law Revision Counsel. 52 USC 10301 – Denial or Abridgement of Right to Vote on Account of Race or Color In redistricting, this has historically meant that when a racial or language minority group is large enough and geographically concentrated enough to form a majority in a reasonably shaped district, and voting patterns show the group is politically cohesive while the majority typically votes as a bloc against its preferred candidates, the state may be required to draw a district giving that group an effective opportunity to elect its chosen representative.
In April 2026 the U.S. Supreme Court decided Louisiana v. Callais, holding that Section 2 now imposes liability only when the evidence supports a strong inference that the state intentionally drew districts to give minority voters less opportunity because of their race. The ruling also requires any illustrative maps offered by challengers to be drawn without using race as a criterion and to satisfy all of the state’s legitimate redistricting goals.6Supreme Court of the United States. Louisiana v. Callais, No. 24-109 (April 29, 2026)
What Could Change for the 2030 Map
Two developments will shape the next round of Illinois maps.
Illinois passed a law in 2021 requiring incarcerated people to be counted at their last known home address rather than at the prison where they are housed, taking effect for the 2030 cycle. The Census Bureau’s traditional approach counts prisoners at their facility, which inflates the population of districts containing large prisons and depletes the urban neighborhoods most prisoners come from. In practice, districts containing major correctional facilities in places like Menard or Pontiac will lose population on paper for the next map, while districts in Chicago and other urban centers will gain it.
The Callais decision raises the bar for Voting Rights Act challenges. Under the new standard, challengers must show a strong inference of intentional discrimination and must demonstrate that racial bloc voting cannot be explained by partisan affiliation alone. For Illinois mapmakers, that means less legal pressure to draw majority-minority districts, and also less legal cover if race becomes the dominant factor in doing so. How it plays out will depend on the demographic and political data that arrive with the 2030 census.
If the General Assembly cannot agree on a plan by June 30 of the year after the census, the Illinois Constitution transfers the job to a bipartisan Legislative Redistricting Commission with its own deadlines and a tiebreaker chosen by random draw.4Illinois General Assembly. Illinois Constitution Article IV – The Legislature – Section 3 Until that happens, the September 2021 maps remain the ones on your ballot.