Illinois State Route 173 runs east-west across Northern Boone County. This is the main east-west surface route in this portion of the county. IL St Rt 173 passes through the following towns in Boone County. Capron Caledonia
IL St Rt 173 is not multi-plexed in Boone County. IL St Rt 173 intersects the following highway in Boone County. Illinois State Route 76, near Caledonia.
