Illinois State Route 108 runs east-west in West-Cental Montgomery County. This route is the main link between Interstate 55 and Carlinville, in Macoupin County. IL St Rt 108 does not pass through any towns in Montgormery County. IL St Rt 108 is not multi-plexed in Montgomery County. IL St Rt 108 intersects the following highway in Montgomery County. Interstate 55, near Honey Bend.