^Looking west from the 4-way intersection with Indiana 237 in Cannelton, April 2018.
Indiana State Route 66 runs in southernmost Indiana, through Evansville and near the Ohio River for much of its length. It begins in New Harmony, at the eastern approach of a now-closed bridge that once carried Illinois 14 over the Wabash River. From New Harmony, Indiana Route 66 heads east into Evansville, switching places with Indiana Route 62 to take its place as the southernmost east-west Indiana highway, near the Ohio River. East of Cannelton, Indiana Route 66 and the Ohio River both take a more northerly turn, and even after the Ohio River turns easterly again, Indiana Route 66 proceeds to zigzag northeasterly before ending at US Route 150 in Hardinsburg.