Poto'mac

Poto'mac, a river of the United States, formed by two branches which rise in the Alleghany Mountains in West Virginia, and unite 15 miles SE. of Cumberland, Maryland, from which point the river flows in a generally south-easterly course 400 miles, and falls into Chesapeake Bay, after forming an estuary nearly 100 miles long, and from 2½ to 7 miles wide. The largest ships can ascend to Washington, and the tide reaches Georgetown. A few miles above Washington the river forms a cataract 35 feet high; and between there and Westport it falls more than 1000 feet. The scenery in this portion of its course is wild and beautiful, especially where it breaks through the Blue Ridge at Harper's Ferry. Its principal affluents are the Shenandoah, Cacapon, and Monacacy. The Poto'mac forms the greater part of the boundary between Virginia and Maryland.