Illinois Route 2 is a north–south state highway in northern Illinois. It currently starts at Illinois Route 40 in Sterling and ends at the Wisconsin state line in South Beloit, very near the intersection with U.S. Route 51, Illinois Route 75 and Illinois Route 251. Illinois 2 is 73.91 miles (118.95 km) long.

Illinois Route 40 is a 112.05-mile-long (180.33 km) north–south route in central portion of the U.S. state of Illinois. It runs from Interstate 74 (I-74) in East Peoria north to IL 78 at Mt. Carroll, just south of U.S. Route 52 and IL 64.