Illinois Route 38 is a west–east state highway that runs across northern Illinois. It runs from U.S. Route 52 (US 52) in downtown Dixon to US 12/US 20/US 45 (Mannheim Road) in Westchester. It runs concurrently with the Lincoln Highway between Dixon and the junction of Illinois Route 31 in Geneva where it transitions via State Street onto Roosevelt Road at the junction of Kirk Road and continues through the western suburbs to its terminus at the junction of Mannheim Road. Roosevelt Road continues on an additional 14 miles without a route designation until terminating at US 41 (Lake Shore Drive).