Potomac

Potomac, a river of the United States, rising from two sources in the Alleghany and the Shenandoah Mountains respectively. Flowing S.E., it separates Maryland from Virginia, is joined by several affluents from those states and from Pennsylvania, the largest of these being the Shenandoah. An estuary opening into Chesapeake Bay forms the mouth of the river, the entire length of which is about 400 miles. Washington stands on its banks, about 125 miles from the sea, and to that, point vessels can ascend.