| State: | IL |
| Type: | IL |
| Maint: | IDOT |
| Route: | 177 |
| Map Custom: | yes |
| Map Notes: | IL 177 highlighted in red |
| Length Mi: | 47.59 |
| Length Round: | 2 |
| Length Ref: | [1] |
| Terminus A: | in Belleville |
| Junction: | in Okawville |
| Terminus B: | in Irvington |
| Direction A: | West |
| Direction B: | East |
| Counties: | St. Clair, Clinton, Washington |
| Established: | 1924[2] |
| Previous Route: | 176 |
| Previous Type: | IL |
| Next Type: | IL |
| Next Route: | 178 |
Illinois Route 177 is an east - west state route in southern Illinois. It runs from Illinois Route 13 in Belleville to U.S. Route 51 in Irvington. This is a distance of 47.59miles.
Illinois 177 overlaps Illinois Route 160 for about [3] from south of New Baden to Okawville.
SBI Route 177 originally ran from New Minden to Okawville. It was extended east to Irvington in 1937, replacing Route 153.[4] In 1967, it was extended west to Belleville on an old routing of Illinois Route 15.[2]