It runs from U.S. Route 52 (US 52) in downtown Dixon to US 12/US 20/US 45 (Mannheim Road) in Westchester.

Roosevelt Road continues on an additional 14 miles without a route designation until terminating at US 41 (Lake Shore Drive).

Illinois 38 runs along the historic Lincoln Highway for much of its length, and parallels Interstate 88 as well.

It enters the Chicago metropolitan area at Elburn, as this border is pushed west with the extension of the Metra rail system.

The ramp to Interstate 290 has an automated gate system that closes during high-volume periods, such as rush hours.

In 1972, as traffic patterns shifted, these alternates to US highways became unnecessary and fell out of favor.