was moved onto the Chicago Skyway and became Toll Business U.S. Route 12 until 1968, when all Business US 12 designations were dropped. In Illinois, the highway has been designated as the Iron Brigade Memorial Highway to honor the Civil War Union Army unit, a designation it also has in Michigan, Indiana, and Wisconsin. Major intersections References External links 12 Illinois Transportation in Chicago Transportation in Cook County, Illinois Transportation in Lake County, Illinois Transportation in McHenry County, Illinois