Entering Illinois from St. Louis, Missouri, the highway originally crossed the Mississippi River at the McKinley Bridge. This first alignment passed through Venice and Madison, eventually becoming IL 203 in northeast Granite City. In 1930, the Chain of Rocks Bridge was opened on Bypass US 66, allowing travelers to circumvent St. Louis. This route met the original Route 66 in Mitchell. The Luna Cafe, Bel-Air Drive-In sign, and the Old Greenway Motel can be found along this stretch of road, as well as The Mustang Corral, a Ford Mustang shop, just before IL 157 on the right hand side eastbound. Route 66 joined IL 157 through Hamel via Edwardsville.