Potomac River flows into the Chesapeake Bay, located along the
mid-Atlantic coast of the United States. The river (main
stem and North Branch) is approximately 383 statute miles long,
with a drainage area of about 14,700 square miles. In terms
of area, this makes the Potomac River the fourth largest river
along the Atlantic coast of the USA and the 21st largest in the
USA. Over 5 million people live within the Potomac
The river forms part of the borders
between Washington, D.C. and Virginia on the left descending bank
and Maryland and Virginia on the river's right descending bank.
The entire lower Potomac River is part of the State of Maryland,
with the exception of a small tidal portion within the District of
Columbia. Except for a small portion of its headwaters in West
Virginia, the North Branch Potomac River is considered part of
Maryland to the low water mark on the opposite bank. The South
Branch Potomac River lies completely within the state of West
Virginia except for its headwaters, which lie in Virginia.
The Potomac River runs 383 miles from the Fairfax Stone in West
Virginia to Point Lookout, Maryland and drains 14,679 square
miles. The average flow is 10,800 ft³/s. The largest flow ever
recorded on the Potomac at Washington, D.C. was in March 1936 when
it reached 425,000 ft³/s. The lowest flow ever recorded at the
same location was 600 ft³/s in September 1966.
The river has two sources. The source of the North Branch is at
the Fairfax Stone located at the junction of Grant, Tucker,
Preston counties in West Virginia. The source of the South Branch
is located near Hightown in northern Highland County, Virginia.
The river's two branches converge just east of Green Spring in
Hampshire County, West Virginia to form the Potomac.
Once the Potomac drops from the Piedmont to the Coastal Plain,
tides further influence the river as it passes through Washington,
D.C. and beyond. Salinity in the Potomac River Estuary increases
thereafter with distance downstream. The estuary also widens,
reaching 11 statute miles wide at its mouth, between Point
Lookout, Maryland and Smith Point, Virginia before flowing into
the Chesapeake Bay.
"Potomac" is a European spelling of an
Algonquian name for a tribe subject to the Powhatan confederacy,
that inhabited the upper reaches of the Northern Neck in the
vicinity of Fredericksburg, Virginia. Some accounts say the name
means "place where people trade" or "the place to which tribute is
brought". The natives called the river above the falls
Cohongarooton, translated as "river of geese", and that area was
renowned in early years for an abundance of both geese and swans.
The spelling of the name has been simplified over the years from "Patawomeke"
(as on Captain John Smith's map) to "Patowmack" in the 18th
century and now "Potomac". Some scholars have also suggested it is
rooted in the ancient Greek for river, "potamos", blended with the
Powhatan name "Patawomeke". The river's name was officially
decided upon as Potomac by the Board on Geographic Names in 1931.
The Potomac River brings together a variety of cultures throughout
the watershed from the coal miners of upstream West Virginia to
the urban residents of the nation's capital and, along the lower
Potomac, the watermen of Virginia's Northern Neck.
Being situated in an area rich in American history and American
heritage has led to the Potomac being nicknamed "the Nation's
River." George Washington, the first President of the United
States, was born in, surveyed, and spent most of his life within
the Potomac basin. All of Washington, D.C., the nation's capital
city, also lies within the watershed.
The 1859 siege of Harper's Ferry at the river's confluence with
the Shenandoah was a precursor to numerous epic battles of the
American Civil War in and around the Potomac and its tributaries.
General Robert E. Lee crossed the river, thereby invading the
North and threatening Washington, D.C., twice in campaigns
climaxing in the battles of Antietam and Gettysburg.
The Patowmack Canal was intended by George Washington to connect
the Tidewater region near Georgetown with Cumberland, Maryland.
Started in 1785 on the Virginia side of the river, it was not
completed until 1802. Financial troubles led to the closure of the
canal in 1830. The Chesapeake and Ohio Canal operated along the
banks of the Potomac in Maryland from 1831 to 1924 and also
connected Cumberland to Washington, D.C. This allowed freight to
be transported around the rapids known as the Great Falls of the
Potomac River, as well as many other, smaller rapids.
Washington, D.C. began using the Potomac as its principal source
of drinking water with the opening of the Washington Aqueduct in
1864, using a water intake constructed at Great Falls.
President Bill Clinton designated the Potomac as one of the
American Heritage Rivers in 1998.