U.S. Route 1 (US 1) in Washington, D.C., passes through from Arlington, Virginia, to Mount Rainier, Maryland, predominantly along surface streets.

Northbound US 1 and Interstate 395 (I-395) enter the District of Columbia from Virginia on the 14th Street bridges.

Southbound US 1 enters the District of Columbia from Maryland on Rhode Island Avenue.

When originally designated in 1926, US 1 entered Washington DC on Bladensburg Road.

US 1 Alternate leaves US 1 at New York Avenue, following US 50 east, and rejoins the highway in Hyattsville, Maryland.