The George Washington Memorial Parkway, colloquially the G.W. Parkway, is a 25-mile-long (40 km) parkway that runs along the south bank of the Potomac River from Mount Vernon, Virginia, northwest to McLean, Virginia, and is maintained by the National Park Service (NPS). It is located almost entirely within Virginia, except for a short portion of the parkway northwest of the Arlington Memorial Bridge that passes over Columbia Island within the District of Columbia.