Illinois
17 congressional districts.
Map
- Very compact (0 to 19)
- Compact (20 to 39)
- Middle (40 to 59)
- Irregular (60 to 79)
- Very irregular (80 to 100)
Select a district for details.
The area outlined with dashes on the map, enlarged so its smaller districts can be seen.
Map used in 2026
2021 enacted plan (HB 1291)
- Drawn by
- the state legislature
- Enacted
- 2021-11-23
- Changed since 2024
- No
Source: All About Redistricting, Loyola Law School (secondary source) (checked 2026-11-04)
Districts
| District | Irregularity | National rank |
|---|---|---|
| IL-01 | Irregularity score 90 Very irregular | 27th least compact |
| IL-02 | Irregularity score 38 Compact | 278th least compact |
| IL-03 | Irregularity score 97 Very irregular | 4th least compact |
| IL-04 | Irregularity score 86 Very irregular | 45th least compact |
| IL-05 | Irregularity score 98 Very irregular | 3rd least compact |
| IL-06 | Irregularity score 78 Irregular | 69th least compact |
| IL-07 | Irregularity score 90 Very irregular | 25th least compact |
| IL-08 | Irregularity score 89 Very irregular | 28th least compact |
| IL-09 | Irregularity score 96 Very irregular | 10th least compact |
| IL-10 | Irregularity score 54 Middle of the pack | 188th least compact |
| IL-11 | Irregularity score 90 Very irregular | 26th least compact |
| IL-12 | Irregularity score 22 Compact | 362nd least compact |
| IL-13 | Irregularity score 96 Very irregular | 7th least compact |
| IL-14 | Irregularity score 59 Middle of the pack | 160th least compact |
| IL-15 | Irregularity score 74 Irregular | 90th least compact |
| IL-16 | Irregularity score 86 Very irregular | 44th least compact |
| IL-17 | Irregularity score 97 Very irregular | 6th least compact |
Scores describe shape, not intent. How scores work
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
Partisan fairness
How the 2024 presidential vote splits across these districts. Kamala Harris (Democrat) won 55.6% of the two-party vote and carried 14 of 17 districts.
- Efficiency gap
- 18.4% Favors Democrats
Counts each party's wasted votes: votes for a losing candidate, plus a winner's votes beyond the half needed to win. The gap is the difference between the two parties' wasted votes, as a share of all votes.
- Mean-median difference
- 0.9 points Favors Republicans
The gap between a party's average vote share across the districts and its share in the middle (median) district. When the middle district leans away from a party's average, that party's voters are packed into a few lopsided districts.
- Declination
- 0.53 Favors Democrats
Compares how lopsided each party's wins are. A party that wins a few districts by huge margins and loses the rest narrowly is at a disadvantage. Runs from 0 (even) to 1.
Votes are 2024 presidential results by precinct, added up within each district. This state used the same districts in 2024 and 2026. These measures show how a map turns one election's votes into seats. They don't show why the lines were drawn, and they shift from one election to the next. How fairness scores work