 It soon leaves IL 3 for the last time to follow IL 143 into downtown Alton and then a short piece of US 67 to reach IL 100, which runs directly along the river for a significant distance before turning inland at Grafton.Rather than cross the Illinois River on the Brussels Ferry, the Great River Road remains with IL 100 alongside the Illinois River, first on the east side to the Hardin Bridge and then on the west side to Kampsville.There it turns west to rejoin the Mississippi River, following IL 96 to north of Hull and former IL 57 to the I-172 interchange near Fall Creek.