Illinois State Route 100 runs north-south in Cass County. It runs along the eastern banks of the Illinois River. IL St Rt 100 passes through the following towns in Cass County. Beardstown
IL St Rt 100 is multi-plexed in Cass County. U.S. Rt. 67, through Cass County.
IL St Rt 100 intersects the following highways in Cass County. Illinois State Route 125, at Beardstown.
