High Quality Content by WIKIPEDIA articles! In the U.S. state of Illinois, U.S. Route 12 is an arterial highway that runs northwest to southeast through the Chicago metropolitan area. It enters Illinois at the Wisconsin border north of Richmond, and exits into Hammond, Indiana from Chicago near the foot of the onramp to the Indiana Toll Road (Interstate 90); as it exits Illinois, the route is also concurrent with U.S. Routes 12 and 41. Within Illinois, U.S. Route 12 runs for a distance of 85.14 miles (137.02 km).