Interstate 474 (I-474) is an Interstate Highway loop route that provides a southern bypass around the north central Illinois city of Peoria. I-474's parent interstate is I-74. As the first digit of the interstate's number is even, it follows the established convention of providing a loop around a city. Interstate 474 is 14.88 miles (23.95 km) long. I-474 is the highest numbered route in the state of Illinois.
Interstate 474 is a modern, Interstate-standard four-lane freeway for its entire length. Prior to 2006, thru truck traffic on I-74 was instructed to use I-474. This is because prior to its 2004-2007 reconstruction, Interstate 74 was significantly below Interstate standard, having numerous 15 mph (24 km/h) onramps and offramps, extremely short merging space for onramps (some less than 500 feet (152 m) in length), and a 50 mph (80 km/h) speed limit through downtown Peoria.
The western terminus of the interstate is at I-74, exit #87A. The eastern terminus of the route is at I-74, exit #100. North of the western terminus, the route continues as Illinois Route 6 with a new series of exit numbers.
I-474 was constructed through the mid-1970s. The now-named Shade-Lohmann Bridge was erected in 1973. During that year, $30.1 million was allocated for acquisition of right-of-way, grading work and overpass/bridge construction across the whole length of the highway.