Illinois State Route 161 is the main east-west highway across Southern Clinton County. It runs from the St. Clair/Clinton County Line, at New Baden, to the Clinton/Marion County Line, at Centralia. IL St Rt 161 passes through the following towns in Clinton County. New Baden
Albers
Germantown Barelso Posey Centralia
IL St Rt 161 is not multi-plexed in Clinton County. IL St Rt 161 intersects the following highways in Clinton County. Illinois State Route 160, near New Baden.