Illinois Route 161
|Maintained by IDOT|
|Length:||67.24 mi (108.21 km)|
|Existed:||1926 – present|
|West end:||St. Clair Avenue in Fairview Heights|
| I-64 in New Baden
US 51 in Centralia
I-57 in Kell
|East end:||IL 37 in Kell|
|Counties:||St. Clair, Clinton, Marion|
Illinois Route 161 (abbreviated IL 161) is an east–west highway with its western terminus at St. Clair Avenue in Fairview Heights and its official eastern terminus at Illinois Route 37 near Kell. This is an official distance of 67.24 miles (108.21 km).
Illinois 161 runs along portions of what once was U.S. Route 50 west of Scott Air Force Base. East of Belleville, it becomes a rural, two-lane surface road. Inside the Centralia city limits, Illinois 161 is coupled into east bound Noleman Street and west bound McCord Street.