# List of Interstate Highways in Illinois

The Interstate Highways in Illinois are all segments of the Interstate Highway System that are owned and maintained by the U.S. state of Illinois. The Illinois Department of Transportation (IDOT), Illinois State Toll Highway Authority (ISTHA), and Skyway Concession Company (SCC) are responsible for maintaining these highways in Illinois. The Interstate Highway System in Illinois consists of 13 primary highways and 11 auxiliary highways which cover 2,248.93 miles (3,619.30 km). The Interstate Highway with the longest section in Illinois is Interstate 57 at 358.57 miles (577.06 km); the shortest is Interstate 41 at 0.90 miles (1.45 km).

## Primary Interstate Highways

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-24 | 38.73 | 62.33 | I-57 in Williamson County | I-24 at Metropolis | 01977-01-011977 | current | |
| I-39 | 123.42 | 198.63 | I-55 in Normal | I-39/I-90 in South Beloit | 01989-01-011989 | current | |
| I-41 | 0.96 | 1.54 | I-94/US 41 in Russell | I-41/I-94/US 41 near Russell | 02015-04-072015 | current | Overlaps I-94 from the US 41 split north to the state line |
| I-55 | 294.38 | 473.76 | I-55/I-64 in East St. Louis | US 41 in Chicago | 01960-01-011960 | current | |
| I-57 | 364.16 | 586.06 | I-57 near Cairo | I-94 in Chicago | 01969-01-011969 | current | Longest Interstate in Illinois |
| I-64 | 128.12 | 206.19 | I-55/I-64 in East St. Louis | I-64 in Grayville | 01974-01-011974 | current | |
| I-66 | — | — | Missouri state line | Kentucky state line | 01991-01-011991 | 02015-01-012015 | Cancelled proposal that was part of the planned East–West TransAmerica Corridor |
| I-70 | 160.38 | 258.11 | I-70 in East St. Louis | I-70 in Clark County | — | — | |
| I-72 | 177.35 | 285.42 | I-72/US 36 in Pike County | I-57 in Champaign | 01970-01-011970 | current | |
| I-74 | 220.34 | 354.60 | I-74/US 6 in Moline | I-74 in Danville | — | — | Everett McKinley Dirksen Memorial Highway |
| I-80 | 163.52 | 263.16 | I-80 in Rock Island County | I-80/I-94/US 6 in Lansing | 01967-01-011967 | current | |
| I-88 | 140.60 | 226.27 | I-80 in Silvis | I-290 in Hillside | 01987-01-011987 | current | Overlaps IL 110 through the entire route, Ronald Reagan Memorial Tollway |
| I-90 | 107.49 | 172.99 | I-39/I-90 in South Beloit | I-90 in Chicago | — | — | |
| I-94 | 77.67 | 125.00 | I-41/I-94/US 41 near Russell | I-80/I-94/US 6 in Lansing | — | — | |
| Former ||||||||

## Auxiliary Interstate Highways

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-155 | 32.13 | 51.71 | I-55 near Lincoln | I-74 in Morton | 01992-01-011992 | current | |
| I-172 | 19.69 | 31.69 | I-72/US 36 in Fall Creek | US 24/IL 336 in Fowler | 01995-01-011995 | current | Overlaps IL 110 through the entire route |
| I-180 | 13.19 | 21.23 | IL 26/IL 71 in Hennepin | I-80 in Bureau County | 01967-01-011967 | current | |
| I-190 | 3.07 | 4.94 | O'Hare International Airport | I-90 in Chicago | 01978-01-011978 | current | Shortest auxiliary Interstate in Illinois, Kennedy Expressway |
| I-255 | 27.05 | 43.53 | I-255/US 50 in Columbia | I-270/IL 255 in Pontoon Beach | 01967-01-011967 | current | |
| I-270 | 14.97 | 24.09 | I-270 in Madison County | I-55/I-70 in Troy | 01956-01-011956 | current | |
| I-280 | 17.60 | 28.32 | I-280 in Rock Island | I-74/I-80 in Colona | — | — | |
| I-290 | 29.84 | 48.02 | I-90/IL 53 in Schaumburg | I-90/I-94 in Chicago | 01955-01-011955 | current | Dwight D. Eisenhower Expressway |
| I-294 Toll | 53.42 | 85.97 | I-80/I-94/US 6/IL 394 in South Holland | I-94 in Northbrook | 01957-01-011957 | current | Longest auxiliary Interstate in Illinois, Tri-State Tollway |
| I-355 | 32.51 | 52.32 | I-80 in New Lenox | I-290 in Itasca | 01989-01-011989 | current | Veterans Memorial Tollway |
| I-474 | 14.88 | 23.95 | I-74/IL 6 in Peoria | I-74 in East Peoria | — | — | Peoria Bypass |
| I-490 Toll | — | — | I-294 in Franklin Park | I-90 in Des Plaines | proposed | — | To be opened by 2026 |
| I-494 | — | — | — | — | — | — | Proposal for Lake Shore Drive |
| I-494 | — | — | — | — | — | — | Proposed and cancelled Crosstown Expressway |
| Former ||||||||

## Business loops

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-55 BL | 13.9 | 22.4 | I-55/I-72/US 36 in Springfield | I-55 in Williams Township | — | — | Serves Springfield |
| I-55 BL | — | — | I-55 in Fogarty | I-55 in Lincoln | — | — | Serves Lincoln |
| I-55 BL | 9.6 | 15.4 | I-55/I-74/US 51 in Bloomington | I-55 in Normal | — | — | Serves Normal and Bloomington |
| I-72 BL | 9.5 | 15.3 | I-72/US 36/US 67 southwest of Jacksonville | I-72 in Jacksonville | — | — | Serves Jacksonville |