How Long Is The Potomac River?
How Long Is The Potomac River? The river is about 11 miles wide be- tween Point Lookout and Smith Point. Upstream, from Great Falls to Harpers Fer- ry, it averages about 1,300 feet in width. The deepest point near Morgantown, Md., in the tidal portion of the river below Wash- ington, D.C., is 107 feet.