| District of Columbia Routes | |
|---|---|
Standard markers for highways in the District of Columbia | |
| Highway names | |
| Interstates | Interstate X (I-X) |
| US Highways | U.S. Route X (US X) |
| State | District of Columbia Route X (DC X) |
| System links | |
District of Columbia Routes are numbered highways maintained by the District of Columbia's District Department of Transportation (DDOT). In addition to these routes, there are several Interstate and United States Numbered highways that pass through Washington, D.C. The metro area is also served by three unnumbered, federally maintained parkways: the Clara Barton Parkway, the Rock Creek and Potomac Parkway, and the George Washington Memorial Parkway (the latter on the west side of the Potomac River, but a portion of it is east of the Boundary Channel).