U.S. Route 34 is an east–west United States highway that runs for 1,122 miles (1,806 km) from north-central Colorado to the western suburbs of Chicago. Through Rocky Mountain National Park it is known as the Trail Ridge Road where it reaches 12,183 ft (3,713 m), making it the highest paved through highway in the United States. The highway's western terminus is Granby, Colorado at U.S. Route 40. Its eastern terminus is in Berwyn, Illinois at Illinois Route 43 and Historic US 66.

U.S. Route 34 becomes a toll road for a short distance in Colorado, where it passes through Rocky Mountain National Park.