# List of state routes in Illinois

The Illinois Routes are the highways in the State Highway System of the U.S. state of Illinois that are not simultaneously part of the Interstate Highway System or the United States Numbered Highway System. These highways are maintained by the Illinois Department of Transportation (IDOT), with the exception of Illinois Route 390 and parts of Illinois Route 56 and Illinois Route 110, which are maintained by the Illinois State Toll Highway Authority (ISTHA), and all routes that enter the Chicago City Limits are maintained by the Chicago Department of Transportation.

## History

Illinois's state route numbers originated in 1918 as State Bond Issues 1 through 46, used to finance the new roads. The numbers of the bond issues were then used to mark the highway routes along the way. Another series of bond issues were authorized in 1924 (47–185) and again were used to mark the roads they paid for. After that the route numbers evolved into a separate system. The State Bond Issue numbers (SBI) remained as inventory designations on the original routes even after the numbered portion was changed, deleted or rerouted. These SBI numbers remain on IDOT district maps to this day and are used along with other designations for bid requests and other official documents.
During the middle part of the 20th century the state numbered routes expanded to new roads around the state. When the United States Numbered Highway System was introduced in the late 1920s many of the new US Routes were already part of the state system and the US number was just added to signposts. During 1930s as the US Highway System matured, redundant state numbers were often removed from US Routes. During 1950s and into 1980s, as the Interstate Highway System started to supplant many US Routes, redundant numbers were removed or replaced with state numbers. After the original Interstate Highways were substantially completed in the early 1970s many state (and US) routes, especially in the Chicago metro area, were removed or shortened as unnecessary.
While US and Interstate systems use even numbers for primary east–west routes and odd for north–south, there is no such rule for Illinois route numbers. Also, three-digit route numbers are usually not related to their one- or two-digit counterpart. There are several exceptions to this however.

## General notes

Illinois has used route numbers from IL 1 through IL 186 inclusive as well as many others up to IL 594.
Illinois has used letter suffixes on several state highways, including "A", "B". "C", "N" (for north) and "S" (for south). A, B and C suffixes were used for spurs of a nearby route, the N and S were legs of IL 113 on either side of the Kankakee River.
Illinois has also used special routes, such as "Business", "Alternate", "City", "Bypass" and "Truck" on state-numbered highways. Only a pair of truck routes as well as a batch of Business Routes remain in Illinois, all other special state highways have been renumbered or the markers removed.

## Primary routes

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| IL 1 | 323.06 | 519.91 | Cave in Rock Ferry in Cave in Rock | I-57 in Chicago | 01918-01-011918 | current | IL 1 was posted on what is now IL 394 from 1957 to 1964, the old road was Alt. IL 1 during that time |
| IL 2 | 73.91 | 118.95 | IL 40 in Sterling | WIS 213 in South Beloit | 01918-01-011918 | current | Originally Rockford to Dixon to Mendota to Cairo; replaced by US 51 south of Mendota |
| IL 3 | 187.44 | 301.66 | US 51/IL 37 in Cairo | IL 100 in Grafton | 01918-01-011918 | current | Originally Morrison to Chester, replaced by other roads including IL 78 and US 67 north of the St. Louis area |
| IL 4 | 170.44 | 274.30 | IL 13/IL 127 in Murphysboro | I-55 Bus./IL 29 in Springfield | 01918-01-011918 | current | Originally Chicago to St. Louis, mostly replaced by US 66 except from Springfield to Staunton where IL 4 was used on the old road and US 66 on the new; IL 4 replaced the old IL 43 Staunton to near Murphysboro |
| IL 4A | — | — | — | — | 01925-01-011925 | 01967-01-011967 | Ran Chicago to Joliet along Archer Av., Replaced by IL 171 |
| IL 5 | — | — | — | — | 01918-01-011918 | 01967-01-011967 | Originally Chicago to East Dubuque, replaced mostly by US 20 except near Rockford until that was replaced later by Business US 20; |
| IL 5 | 15.78 | 25.40 | US 67 in Rock Island | I-80/I-88/IL 92/IL 110 (CKC) in East Moline | 01971-01-011971 | current | replaced IL 190 on the East–West Tollway until 1987 when it was replaced by I-88 east of I-80 |
| IL 6 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Originally Chicago to Fulton, replaced by US 30, later to become Alt. US 30 and now IL 38 |
| IL 6 | 10.11 | 16.27 | I-74/I-474 in Peoria | IL 29 in Mossville | 01971-01-01c. 1971 | current | applied to freeway extension of I-474 around 1982 |
| IL 7 | 28.06 | 45.16 | US 6 in Rockdale | IL 43 in Worth | 01918-01-011918 | current | Originally Chicago to East Moline, replaced west of Orland Park by US 6 about 1928 then extended to Rockdale in 1969 |
| IL 8 | 45.51 | 73.24 | IL 97 in Maquon | US 24 in Washington | 01918-01-011918 | current | Originally Gulfport to Sheldon, removed in parts and replaced by US 34, US 24 and other routes |
| IL 9 | 218.31 | 351.34 | Iowa 2 in Niota | SR 26/SR 352 in Hoopeston | 01918-01-011918 | current | Originally Hamilton to Cheneyville, replaced in part by US 136, IL 41 and IL 9 |
| IL 10 | 91.35 | 147.01 | US 136 in Easton | US 150 in Champaign | 01918-01-011918 | current | Originally Jacksonville to Decatur, later extended to Danville and Havana |
| IL 11 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Originally Terre Haute to St. Louis, replaced by US 40 |
| IL 11 | — | — | — | — | 01945-01-011945 | 01948-01-011948 | replaced by US 40 alternate, and now IL-140 |
| IL 12 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Originally Vincennes, IN to St. Louis, replaced by US 50 |
| IL 13 | 151.54 | 243.88 | IL 157/IL 163 in Cahokia Heights | KY 56 in Old Shawneetown | 01918-01-011918 | current | Originally Old Shawneetown to St. Louis |
| IL 14 | 76.24 | 122.70 | US 51 in Du Quoin | SR 66 in Phillipstown | 01918-01-011918 | current | Originally DuQuoin to Carmi |
| IL 15 | 149.64 | 240.82 | I-55/I-64/US 40/IL 3 in East St. Louis | SR 64 in Mt. Carmel | 01918-01-011918 | current | Originally East St. Louis to Albion |
| IL 16 | 174.66 | 281.09 | IL 100 in Hardin | US 150/IL 1/IL 133 in Paris | 01918-01-011918 | current | Originally Paris to Litchfield, later extended west to Hardin; IL 316 replaced IL 16 after a new road was built from Mattoon to Charleston in 1962 |
| IL 17 | 209.4 | 337.0 | 1st Street in New Boston | SR 2 in Grant Park | 01918-01-011918 | current | Originally Lacon to Grant Park. Ferry at New Boston dropped in 1973 |
| IL 18 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Originally Princeton to Chicago (Ogden Av.) |
| IL 18 | 39.01 | 62.78 | IL 29 in Henry | IL 17 in Blackstone | 01939-01-011939 | current | Replaced IL 89B and 89C |
| IL 19 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Originally Chicago to Harvard on what is now US-14 |
| IL 19 | 33.64 | 54.14 | IL 25 in Elgin | US 41 in Chicago | 01949-01-011949 | current | moved to current route in 1949 |
| IL 20 | — | — | — | — | 01919-01-011919 | 01941-01-011941 | Replaced in 1941 by IL 120 after confusion with the nearby US-20 |
| IL 21 | 28.13 | 45.27 | IL 43 in Niles | US 41 in Gurnee | 01918-01-011918 | current | This is Milwaukee Ave. Originally Antioch to Chicago. |
| IL 22 | 19.7 | 31.7 | US 14 in Fox River Grove | US 41 in Highland Park | 01918-01-011918 | current | Originally the "22 Loop" around the Chicago metro area. It followed the current IL-22, then went to Crystal Lake via US-14, Aurora via IL-31 and Lynwood on US-30. |
| IL 22A | — | — | — | — | 01924-01-011924 | 01925-01-011925 | Became part of IL 63, which was deleted in 1973; Now IL 68 |
| IL 23 | 126.17 | 203.05 | IL 116 in Pontiac | US 14 in Harvard | 01918-01-011918 | current | Part of it (Streator to Pontiac) was once IL 118 |
| IL 24 | — | — | — | — | 01918-01-011918 | 01940-01-011940 | Replaced by IL 29 by 1940 |
| IL 25 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Kankakee to Fairfield, replaced by US-45. |
| IL 25 | 35.04 | 56.39 | US 34 in Oswego | IL 62 in Carpentersville | 01934-01-011934 | current | Reused in the 1930s on current route. |
| IL 26 | 139.35 | 224.26 | IL 116 in East Peoria | WIS 69 in Orangeville | 01918-01-011918 | current | Originally Freeport to Polo, extended north to the state line to replace IL-74 and south to Bureau then E. Peoria replacing IL-89 and IL-87 in part. Rerouted to the I-180 bridge in the 1990s due to a bridge removal over the Illinois River |
| IL 27 | — | — | — | — | 01918-01-011918 | 01934-01-011934 | Was Savanna to Polo, Now part of US 52 |
| IL 28 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Was Sheffield to Galesburg, Now part of US 34 |
| IL 29 | 175.36 | 282.21 | US 51/IL 16 in Pana | US 6/IL 89 in Spring Valley | 01918-01-011918 | current | Originally DePue to Peoria, extended in the 1930s and 40s. |
| IL 30 | — | — | — | — | 01918-01-011918 | 01941-01-011941 | Was Peoria to Galva, Replaced by US-150, IL-17, IL-78, US-34 and IL 91 |
| IL 31 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Was Quincy to Canton, replaced by US-24, IL-78 and IL-100. |
| IL 31 | 58.41 | 94.00 | US 34 in Oswego | US 12 in Richmond | 01937-01-011937 | current | Current route marked in 1937. |
| IL 32 | 69.32 | 111.56 | US 40/IL 33 in Effingham | IL 48 in Cisco | 01918-01-011918 | current | Originally Decatur to Windsor, extended to Effingham in 1936 then to Cisco in 1998. |
| IL 33 | 97.17 | 156.38 | IL 128 in Beecher City | US 50 in Lawrenceville | 01918-01-011918 | current | Originally Effingham to Gordon, extended to current route in stages. |
| IL 34 | 61.74 | 99.36 | Hopkinton Street / Walnut Street in Rosiclare | IL 14/IL 37 in Benton | 01918-01-011918 | current | Originally was a "T" Shaped route from Harrisburg to Elizabethtown and a leg south to Golconda and a ferry went to KY-297 across the Ohio River. Extended to Benton and to Rosiclare in 1937. Part of this is now IL-146. |
| IL 35 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Used from Mound City to US-51, barely 1 mile long, to serve a federal cemetery. This is now part of IL-37 (part of IL-147 for a short time). |
| IL 35 | 2.42 | 3.89 | US 20 in East Dubuque | WIS 35 in East Dubuque | 01938-01-011938 | current | Used from E. Dubuque to the WI State Line, replacing IL-79. |
| IL 36 | — | — | — | — | 01918-01-011918 | 01937-01-011937 | Replaced by IL 94 |
| IL 37 | 155.07 | 249.56 | US 51 in Cairo | US 45 in Watson | 01918-01-011918 | current | |
| IL 38 | — | — | — | — | 01918-01-011918 | 01941-01-011941 | Replaced by IL 16, IL 159 (then IL 112, and IL 138 |
| IL 38 | 89.28 | 143.68 | US 52 in Dixon | US 12/US 20/US 45 in Westchester | 01971-01-011971 | current | |
| IL 39 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Now part of US 150 |
| IL 40 | — | — | — | — | 01918-01-011918 | 01938-01-011938 | became part of IL 88 |
| IL 40 | 112.05 | 180.33 | I-74/IL 29 in East Peoria | IL 78 in Mount Carroll | 01995-01-011995 | current | Formerly IL 88 |
| IL 41 | 37.53 | 60.40 | US 136 in Adair | US 34/IL 110 (CKC)/IL 164 in Galesburg | 01918-01-011918 | current | |
| IL 42 | — | — | — | — | 01918-01-011918 | 01972-01-011972 | Ran from Chicago to Winthrop Harbor, part of it is now IL-173. Was the designation of Sheridan Road |
| IL 42A | — | — | — | — | 01925-01-011925 | 01967-01-011967 | Replaced by IL 43 |
| IL 43 | — | — | — | — | 01918-01-011918 | 01933-01-011933 | Replaced by IL-120 and IL-122. |
| IL 43 | — | — | — | — | 01935-01-011935 | 01963-01-011963 | Former IL-150 and IL-151; replaced by IL-4. |
| IL 43 | 60.3 | 97.0 | US 30 in Frankfort | US 41/IL 120 in Park City | 01967-01-011967 | current | Formerly IL 42A |
| IL 44 | — | — | — | — | 01918-01-011918 | 01940-01-011940 | Now part of US 52 |
| IL 45 | — | — | — | — | 01918-01-011918 | 01934-01-011934 | Became IL 179 in 1936; IL 179 was deleted by 1995 |
| IL 46 | — | — | — | — | 01918-01-011918 | 01938-01-011938 | Became in part US 45 from La Grange to Des Plaines |
| IL 47 | 169.76 | 273.20 | IL 10 in Seymour | WIS 120 in Hebron | 01924-01-011924 | current | |
| IL 48 | 85.38 | 137.41 | IL 127 in Raymond | IL 54 in DeWitt | 01924-01-011924 | current | |
| IL 49 | 140.86 | 226.69 | IL 33 in Willow Hill | US 45/US 52 in Ashkum | 01924-01-011924 | current | Originally Willow Hill (Near Jasper) to Chicago |
| IL 50 | 66.49 | 107.01 | US 45/US 52 in Kankakee | US 41 in Skokie | 01924-01-011924 | current | |
| IL 51 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Now part of US 45 |
| IL 52 | — | — | — | — | 01924-01-011924 | 01938-01-011938 | Replaced by IL 83; Originally Lemont to Lynwood |
| IL 53 | 82.02 | 132.00 | I-55 in Gardner | IL 83 in Long Grove | 01924-01-011924 | current | |
| IL 54 | — | — | — | — | 01924-01-011924 | 01941-01-011941 | Replaced by IL 83; Originally Lemont to Lynwood |
| IL 54 | 109.35 | 175.98 | I-55 in Springfield | US 45 in Onarga | 01972-01-011972 | current | Formerly US 54; Originally Antioch to Lemont |
| IL 55 | — | — | — | — | 01924-01-011924 | 01964-01-011964 | Now IL 56; Originally Chicago to Oak Brook |
| IL 56 | 32.52 | 52.34 | US 30/IL 47 in Sugar Grove | US 12/US 20/US 45 in Bellwood | 01924-01-011924 | current | Butterfield Road |
| IL 57 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Replaced by US 41 and IL-50 |
| IL 57 | 12.59 | 20.26 | I-172/IL 110 (CKC) in Fall Creek | US 24/IL 104 in Quincy | 01949-01-011949 | current | Originally Hull to Quincy. Route was moved to its current routing when I-172, now I-72, was completed. |
| IL 58 | 28.3 | 45.5 | IL 25 in Elgin | US 41 in Skokie | 01924-01-011924 | current | |
| IL 59 | 71.13 | 114.47 | I-55 in Shorewood | IL 173 in Antioch | 01924-01-011924 | current | |
| IL 59A | — | — | — | — | — | — | Replaced by IL 60 |
| IL 60 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Replaced by US 12 |
| IL 60 | 17.22 | 27.71 | IL 120 in Volo | US 41 in Lake Forest | 01967-01-011967 | current | Formerly IL 59A |
| IL 61 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Richmond to Crystal Lake; now IL 31 (then part of US 12) |
| IL 61 | 44.77 | 72.05 | IL 96 in Ursa | US 136/IL 110/IL 336 in Tennessee | 01935-01-011935 | current | |
| IL 62 | 20.82 | 33.51 | IL 31 in Algonquin | IL 83 in Des Plaines | 01924-01-011924 | current | Originally Algonquin to Chicago (Harlem Ave.) on Algonquin Road west of Des Plaines. In Des Plaines, this was on Oakton Street and then in Park Ridge, it was Talcott Road into Chicago. IL 62 originally ended at IL 43 (Harlem Ave.) In 1974, IL 62 was removed east of IL 83 in Des Plaines. |
| IL 63 | — | — | — | — | 01924-01-011924 | 01973-01-011973 | Replaced in part by IL 21, IL 59, and IL 68 |
| IL 64 | 138.61 | 223.07 | US 52/Iowa 64 in Savanna | US 41 in Chicago | 01924-01-011924 | current | |
| IL 65 | — | — | — | — | 01924-01-011924 | 01971-01-011971 | Swapped routes with US 34 |
| IL 66 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Now IL 126 |
| IL 67 | — | — | — | — | 01924-01-011924 | 01940-01-011940 | Replaced in part by IL 176 |
| IL 68 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 131 |
| IL 68 | 25.74 | 41.42 | IL 72 in East Dundee | I-94/US 41 in Glencoe | 01942-01-011942 | current | Dundee Road; Originally Lake Bluff to Russell |
| IL 69 | — | — | — | — | 01924-01-011924 | 01940-01-011940 | Now part of US 52 |
| IL 70 | 19.01 | 30.59 | West Howard Street/Oak Street in Durand | US 20 Bus. in Rockford | 01924-01-011924 | current | Originally Durand to Mendota |
| IL 70A | — | — | — | — | 01924-01-011924 | 01938-01-011938 | Replaced by IL 170 (then IL 186) |
| IL 71 | 69.37 | 111.64 | I-180/IL 29 in Hennepin | US 34 in Oswego | 01938-01-011938 | current | Former IL 7A and IL 89A |
| IL 72 | 110.71 | 178.17 | IL 73 in Lanark | IL 43 in Chicago | 01924-01-011924 | current | Originally Lanark to Starks |
| IL 73 | 29.32 | 47.19 | US 52/IL 64 in Lanark | Wisconsin state line near Winslow | 01924-01-011924 | current | |
| IL 74 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Replaced in part by IL 26 |
| IL 75 | 41.64 | 67.01 | IL 26 in Freeport | WIS 67 in South Beloit | 01924-01-011924 | current | |
| IL 76 | 15.67 | 25.22 | Business US 20 in Belvidere | WIS 140 east of South Beloit | 01924-01-011924 | current | |
| IL 77 | — | — | — | — | 01924-01-011924 | 01936-01-011936 | Replaced by IL 64 |
| IL 77 | — | — | — | — | 01936-01-011936 | 01937-01-011937 | Replaced by US 40 Bypass |
| IL 78 | 215.51 | 346.83 | US 67/Business US 67/IL 104 in Jacksonville | WIS 78 near Warren | 01924-01-011924 | current | |
| IL 79 | 3 | 4.8 | East Dubuque | WI State Line | 01918-01-011918 | 01938-01-011938 | Replaced by IL 35 |
| IL 79 | — | — | Mississippi River | Fall Creek | 01967-01-011967 | 01981-01-011981 | Replaced by IL 336 |
| IL 80 | — | — | — | — | — | 01964-01-011964 | Now part of US 150 and IL 84 |
| IL 81 | 25.78 | 41.49 | US 150 in Lynn Center | IL 78 in Kewanee | 01924-01-011924 | current | |
| IL 82 | 28.84 | 46.41 | IL 17 in Bishop Hill | IL 92 north of Geneseo | 01924-01-011924 | current | |
| IL 83 | — | — | — | — | 01924-01-011924 | 01940-01-011940 | Now part of IL 17 |
| IL 83 | 92.22 | 148.41 | US 30 in Lynwood | WIS 83 north of Antioch | 01941-01-011941 | current | Originally Galva to New Boston on what is now IL 17 |
| IL 83A | — | — | — | — | 01924-01-011924 | 01940-01-011940 | Now unnumbered |
| IL 84 | 93.93 | 151.17 | — | — | 01924-01-011924 | 01937-01-011937 | Replaced by IL 2; now IL 92 |
| IL 84 | 93.93 | 151.17 | US 6 in Colona | WIS 80 near Galena | 01955-01-011955 | current | |
| IL 85 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Now part of US 67 |
| IL 86 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 2 |
| IL 87 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | unbuilt spur to Dixon |
| IL 87 | — | — | — | — | 01941-01-011941 | 01969-01-011969 | Now IL 26 |
| IL 88 | — | — | — | — | 01924-01-011924 | 01995-01-011995 | Replaced the original IL 40 in 1938; now IL 40 |
| IL 88A | — | — | — | — | — | 01938-01-011938 | Replaced partly by IL 17 |
| IL 89 | 55.48 | 89.29 | IL 116 in Metamora | US 34 in LaMoille | 01924-01-011924 | current | |
| IL 89A | — | — | — | — | 01924-01-011924 | 01938-01-011938 | Now part of IL 71 |
| IL 89B | — | — | — | — | 01924-01-011924 | 01939-01-011939 | Now part of IL 18 |
| IL 89C | — | — | — | — | 01924-01-011924 | 01939-01-011939 | Now part of IL 18 |
| IL 90 | 15.8 | 25.4 | IL 78 near Laura | IL 40 near Edelstein | 01924-01-011924 | current | |
| IL 91 | — | — | — | — | 01924-01-011924 | 01934-01-011934 | Replaced by US 150 |
| IL 91 | 40.72 | 65.53 | US 150 in Peoria | US 34/IL 78 in Kewanee | 01939-01-011939 | current | Formerly IL 30 |
| IL 92 | 106.41 | 171.25 | Iowa 92 near Muscatine, Iowa | US 34 in LaMoille | 01939-01-011939 | current | |
| IL 93 | 9.6 | 15.4 | IL 91 in Elmira | IL 40 in Bradford | 01924-01-011924 | current | |
| IL 94 | 128.76 | 207.22 | US 24 in Camp Point | US 67 in Oak Grove | 01924-01-011924 | current | |
| IL 94A | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 164 |
| IL 94B | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 135 |
| IL 95 | 17.12 | 27.55 | IL 41 in Bardolph | IL 97 in Cuba | 01924-01-011924 | current | |
| IL 95A | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 94 |
| IL 96 | 141.16 | 227.17 | IL 100 in Kampsville | IL 94 in Lomax | 01924-01-011924 | current | |
| IL 97 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Replaced by US 124; now IL 116 |
| IL 97 | 104.43 | 168.06 | I-55/I-72/US 36 in Springfield | US 150 in Knoxville | 01938-01-011938 | current | |
| IL 97A | — | — | — | — | — | 01937-01-011937 | Now IL 116 |
| IL 98 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Replaced by IL 10 |
| IL 98 | 8.36 | 13.45 | IL 29 in Pekin | I-155 in Morton | 01939-01-011939 | current | |
| IL 99 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | Replaced by IL 94 and IL 61 |
| IL 99 | 32.08 | 51.63 | IL 104 in Chambersburg | IL 101 in Brooklyn, Schuyler County | 01936-01-011936 | current | |
| IL 100 | 159.09 | 256.03 | US 67 in Alton | IL 78 in Dunfermline | 01924-01-011924 | current | |
| IL 101 | 19.43 | 31.27 | IL 61 in Augusta | US 67 in Littleton | 01924-01-011924 | current | |
| IL 102 | 18.33 | 29.50 | — | — | 01924-01-011924 | 01955-01-011955 | Chatton to Camp Point; now IL 94 and IL 61 |
| IL 102 | 18.33 | 29.50 | US 45/US 52 in Bourbonnais | IL 53 in Wilmington, Will County | 01961-01-011961 | current | Formerly IL 113N |
| IL 103 | 9.18 | 14.77 | US 24 near Ripley | US 67/IL 100 near Beardstown | 01924-01-011924 | current | |
| IL 104 | 125.91 | 202.63 | US 24/IL 57 in Quincy | IL 29 in Taylorville | 01924-01-011924 | current | |
| IL 105 | 18.33 | 29.50 | — | — | 01924-01-011924 | 01937-01-011937 | Meredosia to Quincy; now IL 104 |
| IL 105 | 37.58 | 60.48 | IL 48 in Decatur | I-72 in Monticello | 01945-01-011945 | current | |
| IL 106 | 18.33 | 29.50 | — | — | 01924-01-011924 | 01933-01-011933 | Winchester to Whitehall; became US 36; now 106 again |
| IL 106 | 66.47 | 106.97 | I-72/US 36/IL 110 (CKC) in Hull | US 67 in White Hall | 01938-01-011938 | current | |
| IL 107 | 23.14 | 37.24 | I-72/US 36/US 54 in Pittsfield | IL 99 in Mt. Sterling | 01924-01-011924 | current | |
| IL 108 | 54.06 | 87.00 | IL 100 in Kampsville | I-55 in Raymond | 01924-01-011924 | current | |
| IL 109 | 8.22 | 13.23 | IL 3 in Dow | US 67 in Jerseyville | 01924-01-011924 | current | |
| IL 110 | — | — | — | — | 01924-01-011924 | 01938-01-011938 | Jerseyville to Benld |
| IL 110 | — | — | — | — | 01938-01-011938 | 01949-01-011949 | Nashville to Freeburg; became US 460 |
| IL 110 | 328 | 528 | I-72/US 36/MO 110 in Hull, Illinois | I-90/I-94/I-290 in Chicago | 02010-01-012010 | current | Chicago-Kansas City Expressway; Originally Jerseyville to Benld |
| IL 111 | 82.18 | 132.26 | Lake Drive in Centreville | IL 104 in Waverly | 01924-01-011924 | current | |
| IL 112 | — | — | — | — | 01924-01-011924 | 01964-01-011964 | Now IL 159; Originally Royal Lakes to Edwardsville |
| IL 113 | 33.95 | 54.64 | IL 47 in Mazon | IL 17 in Kankakee | 01924-01-011924 | current | Formerly 113S |
| IL 113N | — | — | — | — | 01940-01-011940 | 01961-01-011961 | Now IL 102 |
| IL 113S | — | — | — | — | 01940-01-011940 | 01961-01-011961 | Now IL 113 |
| IL 114 | 7.40 | 11.91 | IL 1/IL 17 in Momence | SR 10 near Lake Village, Indiana | 01924-01-011924 | current | |
| IL 115 | 63.37 | 101.98 | IL 9 in Elliott | US 45/US 52 in Kankakee | 01924-01-011924 | current | |
| IL 116 | 176.07 | 283.36 | US 34/IL 94 in Gladstone | US 45 in Ashkum | 01924-01-011924 | current | |
| IL 116A | — | — | — | — | 01924-01-011924 | 01994-01-011994 | Replaced by IL 117 |
| IL 117 | 33.85 | 54.48 | I-74 in Goodfield | IL 17 in Toluca | 01924-01-011924 | current | |
| IL 118 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Originally Streator to Pontiac on what is now IL 23 |
| IL 118 | — | — | — | — | 01935-01-011935 | 01938-01-011938 | Replaced by DuPage CH 7 |
| IL 119 | 7.78 | 12.52 | US 136/IL 1 west of Alvin | SR 28 east of Alvin | 01924-01-011924 | current | Originally Heyworth to the Indiana Line north of Danville |
| IL 119A | — | — | — | — | 01924-01-011924 | 01937-01-011937 | |
| IL 120 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Havana to Mason City on what is now IL 119 |
| IL 120 | 34.48 | 55.49 | US 14 in Woodstock | IL 131 in Waukegan | 01941-01-011941 | current | Belvidere Road; Formerly IL 20 |
| IL 121 | 109.48 | 176.19 | IL 130 in Greenup | I-55/IL 10 in Lincoln | 01924-01-011924 | current | Originally Peoria to Decatur, then to the Indiana line, near Chrisman |
| IL 122 | 31.53 | 50.74 | IL 29 in Green Valley | IL 9 in Danvers | 01924-01-011924 | current | Originally Bloomington to Havana |
| IL 123 | 33.72 | 54.27 | IL 125 in Pleasant Plains | I-55 in Williamsville | 01924-01-011924 | current | Originally Alexander to Athens |
| IL 124 | 5.71 | 9.19 | IL 123 in Williamsville | Business I-55 in Sherman | 01924-01-011924 | current | Originally Athens to Springfield on what is now IL 29 |
| IL 125 | 37.1 | 59.7 | US 67/IL 100 in Beardstown | IL 97 in Pleasant Plains | 01924-01-011924 | current | Originally Springfield to Virginia |
| IL 126 | — | — | — | — | 01924-01-011924 | 01932-01-011932 | Springfield to Litchfield; became US 66 |
| IL 126 | 17.25 | 27.76 | IL 47 in Yorkville | I-55 near Bolingbrook | 01935-01-011935 | current | Formerly IL 66; Originally Springfield to Litchfield |
| IL 127 | 167.53 | 269.61 | IL 3 in Tamms | I-55/IL 48 in Raymond | 01924-01-011924 | current | |
| IL 127A | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 143 |
| IL 128 | 55.57 | 89.43 | I-70 in Altamont | IL 121 in Dalton City | 01924-01-011924 | current | |
| IL 128A | — | — | — | — | — | 01938-01-011938 | |
| IL 129 | — | — | — | — | 01924-01-011924 | 01936-01-011936 | Effingham to Windsor; now IL 32 |
| IL 129 | 4.06 | 6.53 | IL 113 in Braidwood | I-55 in Wilmington | 01960-01-011960 | current | Washington Street; Originally Effingham to Windsor on what is now IL 32 |
| IL 130 | 135.87 | 218.66 | IL 1 in Grayville | I-74 in Urbana | 01924-01-011924 | current | Originally Charleston to Albion |
| IL 130A | 5 | 8.0 | — | — | 01930-01-011930 | 01942-01-011942 | Newton to Sainte Marie |
| IL 131 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Mattoon to Greenup; now IL 121 |
| IL 131 | 15.15 | 24.38 | IL 176 in Lake Bluff | WIS 31 near Pleasant Prairie, Wisconsin | 01938-01-011938 | current | Green Bay Road |
| IL 132 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Decatur to Mattoon; now IL 121 |
| IL 132 | 13.57 | 21.84 | IL 59 in Fox Lake Hills | IL 131 in Waukegan | 01950-01-011950 | current | Grand Avenue |
| IL 133 | 52.05 | 83.77 | IL 32 in Lovington | US 150/IL 1/IL 16 in Paris | 01924-01-011924 | current | |
| IL 134 | — | — | — | — | 01924-01-011924 | 01933-01-011933 | Paris to Indiana; now US 150 |
| IL 134 | 5.62 | 9.04 | US 12/IL 59 in Fox Lake | IL 120 in Hainesville | 01950-01-011950 | current | |
| IL 135 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | IL-1 to the Wabash River bridge at Hutsonville |
| IL 135 | 20.31 | 32.69 | IL 164 in Kirkwood | US 67 in Alexis | 01937-01-011937 | current | |
| IL 136 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | IL-1 to Flat Rock |
| IL 136 | 3.22 | 5.18 | Iowa 136 in Fulton | US 30 east of Fulton | 01967-01-011967 | current | |
| IL 137 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | IL-1 to St. Francisville |
| IL 137 | 23.49 | 37.80 | IL 83 in Grayslake | WIS 32 in Winthrop Harbor | 01953-01-011953 | current | J-Shaped Highway |
| IL 138 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Mt. Carmel to Grayville; replaced by IL-1 |
| IL 138 | 14.95 | 24.06 | IL 159 in Bunker Hill | Illinois Street in Mt. Olive | 01942-01-011942 | current | Originally Mt. Carmel to Grayville |
| IL 139 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Now IL 14; Originally Caramelville to Wabash River Bridge |
| IL 140 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Fairfield to Cave in Rock; replaced by IL-1 |
| IL 140 | 52.05 | 83.77 | IL 143 in Alton | US 40 near Mulberry Grove | 01935-01-011935 | current | Originally Fairfield to Cave in Rock |
| IL 141 | 18.17 | 29.24 | US 45 north of Texas City | SR 62 east of New Haven | 01924-01-011924 | current | |
| IL 142 | 55.06 | 88.61 | Calhoun Street in Equality | I-57 in Mt. Vernon | 01924-01-011924 | current | |
| IL 142A | — | — | — | — | 01924-01-011924 | 01942-01-011942 | Now IL 242; replaced by IL-147 |
| IL 143 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Benton to Harrisburg; replaced by IL-34 |
| IL 143 | 47.96 | 77.18 | US 67 in Alton | IL 127 in Tamalco | 01937-01-011937 | current | Originally Benton to Harrisburg |
| IL 144 | — | — | — | — | 01924-01-011924 | 01964-01-011964 | Now IL 149; Originally Grimsby to Murphysboro |
| IL 145 | 43.47 | 69.96 | US 45 in Metropolis | US 45/IL 34 in Harrisburg | 01924-01-011924 | current | |
| IL 146 | 92.93 | 149.56 | MO 34/MO 74 in East Cape Girardeau | IL 1 in Cave-In-Rock | 01924-01-011924 | current | |
| IL 147 | — | — | — | — | 01924-01-011924 | 01934-01-011934 | Marion to Cairo; now IL 37 |
| IL 147 | — | — | — | — | 01942-01-011942 | 01946-01-011946 | McLeansboro to Wayne City; replaced by IL 142, now IL 242 |
| IL 147 | 12.81 | 20.62 | IL 146 in Vienna | IL 145 in Eddyville | 01965-01-011965 | current | Originally Marion to Cairo on now what IL 37 |
| IL 148 | 54.85 | 88.27 | IL 37 in Pulleys Mill | IL 37/IL 142 in Mt. Vernon | 01924-01-011924 | current | |
| IL 149 | 45.92 | 73.90 | IL 3 in Gorham | IL 34 in Thompsonville | 01924-01-011924 | current | Formerly IL 144 |
| IL 150 | 24.19 | 38.93 | MO 51 in Chester | IL 154 in Cutler | 01924-01-011924 | current | Originally Cairo to Harmel |
| IL 151 | 7.84 | 12.62 | — | — | 01924-01-011924 | 01937-01-011937 | replaced by Illinois 43; now Illinois 4 |
| IL 151 | 7.84 | 12.62 | IL 3 in Jacob | IL 4 in Ava | 01940-01-011940 | current | Originally Steeleville to Murphysboro |
| IL 152 | 6.76 | 10.88 | IL 13/IL 127 in Pyatts | US 51 in Du Quoin | 01924-01-011924 | current | |
| IL 153 | 18.35 | 29.53 | IL 154 in Sparta | IL 15 in Addieville | 01924-01-011924 | current | Originally Eden to Irvington |
| IL 154 | 63.63 | 102.40 | IL 3/IL 159 in Red Bud | IL 37 in Whittington | 01924-01-011924 | current | Originally Pinkeyville to Sunfield |
| IL 155 | 10.81 | 17.40 | Fort de Chartres State Historical Site | IL 3 in Ruma | 01924-01-011924 | current | |
| IL 156 | 22.95 | 36.93 | South Meyer Avenue/C Road in Valmeyer | IL 13 in New Athens | 01924-01-011924 | current | |
| IL 157 | 33.50 | 53.91 | IL 3 in Cahokia | IL 140 in Hamel | 01924-01-011924 | current | |
| IL 158 | 25.81 | 41.54 | IL 3 in Columbia | I-64/US 50 in O'Fallon | 01924-01-011924 | current | |
| IL 159 | 64.90 | 104.45 | IL 3/IL 154 in Red Bud | IL 16 in Royal Lakes | 01924-01-011924 | current | |
| IL 160 | — | — | — | — | 01924-01-011924 | 01935-01-011935 | Alton to Greenville; renumbered IL 140 |
| IL 160 | 46.06 | 74.13 | IL 15 in Addieville | IL 140 in Alhambra | 01959-01-011959 | current | Originally Alton to Greenville |
| IL 161 | 67.24 | 108.21 | St. Clair Avenue in Fairview Heights | IL 37 in Kell | 01924-01-011924 | current | Originally Carlyle to Belleville |
| IL 162 | — | — | — | — | 01924-01-011924 | 01938-01-011938 | Spring Valley to LaMoille; replaced by IL 89 |
| IL 162 | 16.36 | 26.33 | IL 203 in Granite City | US 40 in Troy | 01954-01-011954 | current | Originally Spring Valley to LaMoille |
| IL 163 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | IL 1 to Palestine; replaced by IL 33 |
| IL 163 | 9.89 | 15.92 | IL 158 in Millstadt | IL 15 in Alorton | 01954-01-011954 | current | Originally IL 1 to Palestine |
| IL 164 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Pekin to west of Bloomington; replaced by IL 9 |
| IL 164 | 35.70 | 57.45 | US 34 in Gladstone | US 34/IL 41/IL 110 (CKC) in Galesburg | 01937-01-011937 | current | Originally Pekin to west of Bloomington |
| IL 165 | 29.64 | 47.70 | IL 9 in Merna | IL 47 in Sibley | 01924-01-011924 | current | |
| IL 166 | 14.43 | 23.22 | US 45 in New Burnside | IL 13 in Pittsburg | 01924-01-011924 | current | |
| IL 167 | 12.24 | 19.70 | US 34 in Wataga | IL 180 in Victoria | 01924-01-011924 | current | |
| IL 168 | — | — | — | — | 01924-01-011924 | 01941-01-011941 | Now IL 97 |
| IL 169 | — | — | — | — | 01924-01-011924 | 01939-01-011939 | Shelbyville to Dalton City; replaced by IL 128 |
| IL 169 | 9.04 | 14.55 | IL 37 in Karnak | US 45 in New Columbia | 01949-01-011949 | current | Originally Shelbyville to Dalton City |
| IL 170 | — | — | — | — | 01924-01-011924 | 01937-01-011937 | Red Bud to Sparta; replaced by IL 154 |
| IL 170 | 25 | 40 | IL 23 in Cornell | US 6 in Seneca | 01945-01-011945 | current | Formerly IL 70A and IL 186; originally Red Bud to Sparta |
| IL 171 | — | — | — | — | 01924-01-011924 | 01936-01-011936 | Thomson to IL 78 |
| IL 171 | 38.61 | 62.14 | US 6 in Joliet | IL 72 in Chicago | 01946-01-011946 | current | Formerly IL 4A and IL 213; originally Thomson to IL 78 |
| IL 172 | — | — | — | — | 01924-01-011924 | 01936-01-011936 | Libertyville to Gurnee; replaced by IL 63 and now is part of IL 21 |
| IL 172 | 13.06 | 21.02 | IL 92 in Yorktown | IL 40 in Tampico | 01946-01-011946 | current | Originally Libertyville to Gurnee |
| IL 173 | 66.20 | 106.54 | IL 251 in Machesney Park | IL 137 in Zion | 01924-01-011924 | current | |
| IL 174 | 5.3 | 8.5 | IL 88 in Peoria | IL 91 west of Alta | 01924-01-011924 | 01983-01-011983 | |
| IL 175 | 2 | 3.2 | US 24/IL 9 near Glasford | Glasford | 01924-01-011924 | 01935-01-011935 | |
| IL 176 | 41.28 | 66.43 | IL 23 in Marengo | IL 131 in Lake Bluff | 01924-01-011924 | current | Formerly IL 67 |
| IL 177 | 47.59 | 76.59 | IL 13/IL 158/IL 159 in Belleville | US 51 in Irvington | 01924-01-011924 | current | |
| IL 178 | 8.49 | 13.66 | Ed Lambert Road in Lowell | I-80 in North Utica | 01924-01-011924 | current | |
| IL 179 | 16.3 | 26.2 | IL 251 near Rutland | IL 18 near Streator | 01924-01-011924 | 01995-01-011995 | Part originally IL 45 |
| IL 180 | 15.43 | 24.83 | US 150 in Williamsfield | IL 17 in Victoria | 01924-01-011924 | current | |
| IL 181 | — | — | — | — | 01924-01-011924 | 01948-01-011948 | Now IL 33 |
| IL 182 | — | — | — | — | 01924-01-011924 | 01941-01-011941 | Now IL 161 |
| IL 183 | — | — | — | — | 01924-01-011924 | 01984-01-011984 | Now IL 154 |
| IL 184 | 5.87 | 9.45 | IL 149 in Royalton | IL 14 in Mulkeytown | 01924-01-011924 | current | |
| IL 185 | 49.88 | 80.27 | IL 127 in Taylor Springs | IL 37 in Farina | 01924-01-011924 | current | |
| IL 186 | — | — | — | — | 01938-01-011938 | 01945-01-011945 | Now IL 170 |
| IL 190 | — | — | — | — | 01966-01-011966 | 01971-01-011971 | Renumbered IL 5; now I-88 |
| IL 192 | 8.31 | 13.37 | IL 92 in Illinois City | IL 94 in Taylor Ridge | 01955-01-011955 | current | |
| IL 194 | 16.7 | 26.9 | I-90/IL 53 in Rolling Meadows | I-94 in Chicago | 01960-01-011960 | 01978-01-011978 | Now I-90/I-94 in Chicago |
| IL 199 | — | — | — | — | 01969-01-011969 | 01980-01-011980 | Now IL 92 |
| IL 203 | 9.51 | 15.30 | Collinsville Road in Fairmont City | I-270 in Granite City | 01964-01-011964 | current | |
| IL 213 | — | — | — | — | — | 01946-01-011946 | Now IL 171 |
| IL 226 | — | — | — | — | — | 01946-01-011946 | Replaced by IL 172 |
| IL 242 | 18.67 | 30.05 | IL 142 in McLeansboro | IL 15 in Wayne City | 01924-01-011924 | current | Formerly IL 142A |
| IL 250 | 33.44 | 53.82 | US 50 in Noble | Business US 50 in Lawrenceville | 01965-01-011965 | current | |
| IL 251 | 135.32 | 217.78 | I-39/US 51 in Hudson | US 51/IL 75 in South Beloit | 01982-01-011982 | current | Formerly US 51 in North Central Illinois |
| IL 255 | 23.3 | 37.5 | I-255/I-270 in Pontoon Beach | US 67 in Godfrey | 01998-01-011998 | current | Alton Bypass |
| IL 267 | 59 | 95 | US 67/IL 111 in Godfrey | Business I-72/Business US 67/IL 104 in Jacksonville | 01965-01-011965 | current | |
| IL 316 | — | — | — | — | — | 01981-01-011981 | Now part of IL 16 |
| IL 336 | 80 | 130 | I-172/US 24/IL 110 (CKC) in Quincy | US 136/IL 110 (CKC) in Macomb | 01990-01-011990 | current | |
| IL 351 | 8.55 | 13.76 | IL 71/IL 251 in Oglesby | I-80 in LaSalle | 01966-01-011966 | current | Formerly Business US 51 in LaSalle |
| IL 390 Toll | 9.80 | 15.77 | US 20 in Hanover Park | IL 83 in Bensenville | 02013-01-012013 | current | Formerly the Elgin–O'Hare Expressway |
| IL 394 | 14.63 | 23.54 | IL 1 near Beecher | I-80/I-94/I-294 in South Holland | 01956-01-011956 | current | |
| IL 594 | 3.07 | 4.94 | O'Hare International Airport in Chicago | IL 194 in Chicago | 01971-01-011971 | 01978-01-011978 | Now I-190 |
| Former ||||||||

## Inventory routes

Illinois uses unique "inventory number" signage on rural roads that are owned or maintained by IDOT but may or may not be part of the US or Illinois highway systems. These number signs are white squares, with a green divided circle. The county name is within the dividing line, the mileage from the county line is in the lower half and the inventory or route number in the upper. Number series vary between IDOT Districts, in some areas the number used on otherwise unnumbered routes are a derivative of the former number (i.e.: "913" used on a section of former IL 13) or a sequential number unrelated to the original or former number (such as the 8900 series numbers used in the Galesburg–Macomb area). On many US and Illinois Routes the posted number is used, with or without a preceding descriptor. These signs are not intended for navigation as route numbers are but rather as guides for IDOT crews and contractors and to identify specific intersections, culverts or other features.