Illinois State Route 18 is a short east-west highway in Northern Marshall County. It is one of two bridges over the Illinois River in the county. IL St Rt 18 passes through the following town in Marshall County. Henry
WB IL St Rt 18 east of Henry. The IL St Rt 18 bridge over the Illinois River at Henry. EB IL St Rt 18 at the Illinois River. EB IL St Rt 18 crossing the Illinois River. EB IL St Rt 18 in Henry. A Marshall County mile marker. The western end marker.
