U.S. Federal Route 50 runs east-west across much of the Northern regions of St. Clair County. Near O'Fallon, this highway runs along the interstates into the Metro-East of St. Louis. U.S. Rt. 50 passes through the following towns in St. Clair County. Lebanon
O'Fallon
Shiloh Fairview Heights
Caseyville East St. Louis
Centreville
Alorton
Sauget
Cahokia
Dupo U.S. Rt. 50 is multi-plexed in St. Clair County. Illinois State Route 4, at Lebanon.
A set of junction markers on EB U.S. Rt. 50/NB IL St Rt 4 in Lebanon. EB U.S. Rt. 50/NB IL St Rt 4 in Lebanon. A BGS on EB I-64/U.S. Rt. 50. EB U.S. Rt. 50/IL St Rt 158 in O'Fallon. A BGS on NB IL St Rt 158. A BGS on Old U.S. Rt. 50 in O'Fallon. EB I-64/U.S. Rt. 50 near IL St Rt 157 in Caseyville. BGS on SB I-255. NB I-255/EB U.S. Rt. 50 near Frank Holten State Park. BGS on WB IL St Rt 15. NB I-255/WB U.S. Rt. 50 at IL St Rt 3. A set of junction markers on NB Old IL St Rt 3.