List of U.S. Routes in Washington

The U.S. Routes in Washington are segments of the United States Numbered Highway System that are owned and maintained by the U.S. state of Washington through the Washington State Department of Transportation (WSDOT). The United States Numbered Highway System in Washington covers 1,870 mi and consists of eight highways, divided into four primary routes and four auxiliary routes.

The United States Numbered Highway System was approved and established on November 11, 1926 by the American Association of State Highway Officials (AASHO) and included eleven routes traveling through Washington.

In 1961, the state introduced a set of route markers in Olympia that were colored based on destination and direction rather than route.