Illinois District 13

96 Very irregular

Less compact than 99% of other congressional districts.

7th least compact of 429 nationally, 4th of 17 in Illinois.

A score describes shape, not intent. Coastlines, rivers and the Voting Rights Act can all make a district irregular. How scores work

The three measures

Polsby-Popper: 0.11at least as compact as 10% of districts on this measure
Area compared with perimeter. Low for jagged or snaking edges.
Reock: 0.12among the least compact 1% of districts on this measure
Area compared with the smallest circle around the district, counting only land. Low for stretched shapes.
Convex hull: 0.39among the least compact 1% of districts on this measure
Area compared with a rubber band stretched around the district, counting only land. Low for bites and tentacles.

Each measure runs from 0 to 1, where 1 is a perfect circle or a shape with no dents.

The state's edge

6% of this district's border is the state's edge: a coastline, a national border or a state line. Mapmakers don't choose those lines. A ragged one, like a coastline or a river, lowers Polsby-Popper. Reock and convex hull count only the state's own land, so water and neighboring states don't count against them. More on the state's edge

Cities and towns

The largest places with people in this district, from the 2020 Census. A place split between districts shows how many of its residents live in this one.

Springfield city95,885 of its 114,394 residents
Champaign cityall 88,302 residents
Decatur city42,794 of its 70,522 residents
Belleville city39,179 of its 42,404 residents
Urbana cityall 38,336 residents
Granite City cityall 27,549 residents
Edwardsville city25,260 of its 26,808 residents
Alton city23,700 of its 25,676 residents
Collinsville city20,066 of its 24,366 residents
East St. Louis cityall 18,469 residents

And 84 smaller places. 13% of this district's people live outside any city, town or named community. How places are counted

2024 presidential vote

Kamala Harris 55.3%, Donald Trump 44.7%

Shares of the votes for the two of them; other candidates are left out. Illinois used the same lines in 2024, so this is added up from precinct results. A precinct split between districts is divided by its House votes, so the figures are close estimates. Where the votes come from

U.S. House

Statewide results from Illinois for the November 3, 2026 election aren't available yet.

Where this comes from

Illinois's senators

Tammy Duckworth, Democrat
Richard J. Durbin, DemocratSeat on the November 3, 2026 ballot: results aren't available yet.

Senators are elected by the whole state, so district lines don't change who they are. Senators serving as of November 6, 2026. Senators elected in November 2026 take office January 3, 2027. Where this comes from

Where it sits in Illinois

Very compact (0 to 19)
Compact (20 to 39)
Middle (40 to 59)
Irregular (60 to 79)
Very irregular (80 to 100)