The system of United States Numbered Highways (often called U.S. Routes or U.S. Highways) is an integrated system of roads and highways in the United States numbered within a nationwide grid. As these highways were coordinated among the states, they are infrequently referred to as Federal Highways, but they have always been maintained by state or local governments since their initial designation in 1926. There has never been any de jure federal funding difference between these routes and any other state highways. The numbers and locations are coordinated by the American Association of State Highway and Transportation Officials (AASHTO), in which the only federal involvement is a non-voting seat for the United States Department of Transportation. The Interstate Highway System has largely replaced the U.S. Highways for through traffic, though many important regional connections are still made by U.S. Highways, and new routes are still being added.

The very similar Trans-Canada Highway is often considered the Canadian counterpart to the U.S. Highway System, although it is much more limited in scope.