The Potomac River (IPA: [pə'toʊmæk]) is a river located on the central eastern coast of the United States. The Potomac flows from Fairfax Stone in West Virginia, snakes between the mountains and through the valleys of Appalachia and empties into the Chesapeake Bay near Point Lookout, Maryland. The river's length is reported as 270 to 380 miles long. The river is navigable to ocean going vessels as far upstream as Washington DC. Many consider the Potomac one of the "one of the most beautiful and bountiful rivers on the East Coast". 
The Potomac drains a watershed of 14,670 square miles in Virginia, West Virginia, Maryland, the District of Columbia and Pennsylvania. Several famous and major rivers make-up this watershed. In Maryland, these tributaries include the Monocacy, Savage, and St. Mary's Rivers. In Virginia, the both forks of the Shenandoah River and the Occoquan River feed into the Potomac River system. In West Virginia, the South Branch and Cacapon Rivers flow into the Potomac, while in Pennsylvania the Conococheague Creek and Antietam Creek flow into the river. In Washington D.C., the Anacostia River empties into the Potomac.
In the downtown Washington area, four bridges (14th Street, Memorial, Theodore Roosevelt, Key), some with multiple parallel spans, are major commuter arteries between the District of Columbia and Virginia. There are also bridges for long-haul railroads and the Metro subway system. Two large bridges, Cabin John in the western suburbs and Woodrow Wilson in the east, connect Virginia and Maryland. Reagan National Airport is on the Virginia side.
Relatively few government buildings are actually on the Potomac, the Pentagon Building being a notable exception, along with some military facilities to the south.
Today, more than five million people live in the Potomac watershed. The River is still home to a wide variety of fish and wildlife.
The Potomac River's waters have served as a natural resource and transportation route for more than ten thousand years. Long before Europeans colonized America, the Potomac supported Native Americans who relied on the river's natural abundance. In 1608, Captain John Smith of Jamestowne was among the first Europeans to ever visit the Potomac, sometimes referred to in those days as the Potowmack . The Potomac's crabs, oysters and fish were a major factor in the success of Tidewater colonies in Maryland and Virginia. Many important figures in American history such as George Washington and Robert E. Lee had homes and lived along the banks of the Potomac. Mount Vernon, Washington's home, remains one of the most popular tourist destinations on the Potomac. Because the Potomac makes its way alongside America's capital, the history of the Potomac is tied the history of the nation. 
- Potomac River. Oxford Dictionaries. Oxford University Press (2014). Retrieved on 22 April 2014.
- Waters of Potowmack by by Paul Metcalf University of Virginia Press ISBN 0-8139-2042-6