Potomac River
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The Potomac River () is in the Mid-Atlantic region of the United States and flows from the Potomac Highlands in
West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...
to
Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Ea ...
in
Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...
. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data
The National Map
. Retrieved August 15, 2011
with a
drainage area A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...
of , and is the fourth-largest river along the
East Coast of the United States The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the region encompassing the coast, coastline where the Eastern United States meets the Atlantic Ocean; it has always pla ...
. More than 6 million people live within its watershed. The river forms part of the borders between Maryland and
Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...
, on the left descending bank, and West Virginia and
Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...
on the right descending bank. Except for a small portion of its headwaters in West Virginia, the
North Branch Potomac River The North Branch Potomac River flows from Fairfax Stone in West Virginia to its confluence with the South Branch Potomac River near Green Spring, West Virginia, where it turns into the Potomac River proper. Course From the Fairfax Stone, th ...
is considered part of Maryland to the low-water mark on the opposite bank. The
South Branch Potomac River The South Branch Potomac River has its River source, headwaters in northwestern Highland County, Virginia, near Hightown, Virginia, Hightown along the eastern edge of the Allegheny Front. After a river distance of ,U.S. Geological Survey. Nationa ...
lies completely within the state of West Virginia except for its
headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...
, which lie in Virginia. All navigable parts of the river were designated as a
National Recreation Trail The National Trails System is a series of trails in the United States designated "to promote the preservation of, public access to, travel within, and enjoyment and appreciation of the open-air, outdoor areas and historic resources of the Nati ...
in 2006, and the
National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...
(NOAA) designated an portion of the river in Charles County, Maryland, as the Mallows Bay–Potomac River National Marine Sanctuary in 2019. The river has significant historical and political significance, as the nation's capital of Washington, D.C. is located on its banks, as is
Mount Vernon Mount Vernon is the former residence and plantation of George Washington, a Founding Father, commander of the Continental Army in the Revolutionary War, and the first president of the United States, and his wife, Martha. An American landmar ...
, the home of
George Washington George Washington (, 1799) was a Founding Fathers of the United States, Founding Father and the first president of the United States, serving from 1789 to 1797. As commander of the Continental Army, Washington led Patriot (American Revoluti ...
. During the American Civil War, the river became the boundary between the Union and the Confederacy, and the Union's largest army, the
Army of the Potomac The Army of the Potomac was the primary field army of the Union army in the Eastern Theater of the American Civil War. It was created in July 1861 shortly after the First Battle of Bull Run and was disbanded in June 1865 following the Battle of ...
, was named after the river.


Course

The Potomac River runs from
Fairfax Stone Historical Monument State Park Fairfax Stone Historical Monument State Park is a West Virginia state park commemorating the Fairfax Stone, a surveying, surveyor's marker and boundary marker, boundary stone at the source of the North Branch Potomac River, North Branch of the P ...
in West Virginia on the
Allegheny Plateau The Allegheny Plateau ( ) is a large dissected plateau area of the Appalachian Mountains in western and central New York, northern and western Pennsylvania, northern and western West Virginia, and eastern Ohio. It is divided into the unglacia ...
to Point Lookout, Maryland, and drains . The length of the river from the junction of its North and South Branches to Point Lookout is . The river has two sources. The source of the North Branch is at the Fairfax Stone located at the junction of Grant, Tucker, and Preston counties in
West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...
. 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. As it flows from its
headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...
down to the Chesapeake Bay, the Potomac traverses five geological provinces: the
Appalachian Plateau The Appalachian Plateau is a series of rugged dissected plateaus located on the western side of the Appalachian Mountains. The Appalachian Mountains are a range that run from Nova Scotia in Canada to Alabama in the United States. The Appalachi ...
, the Ridge and Valley, the Blue Ridge, the
Piedmont Plateau The Piedmont ( ) is a plateau region located in the Eastern United States. It is situated between the Atlantic Plain and the Blue Ridge Mountains, stretching from New York in the north to central Alabama in the south. The Piedmont Province i ...
, and the
Atlantic coastal plain The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
. Once the Potomac drops from the
Piedmont Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...
to the
Coastal Plain A coastal plain (also coastal plains, coastal lowland, coastal lowlands) is an area of flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and an upland area. Formation Coastal plains can f ...
at the Atlantic Seaboard fall line at Little Falls,
tides Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...
further influence the river as it passes through Washington, D.C., and beyond.
Salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...
in the Potomac River Estuary increases thereafter with distance downstream. The
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...
also widens, reaching 11 statute miles (17 km) wide at its mouth, between Point Lookout, Maryland, and Smith Point, Virginia, before flowing into the Chesapeake Bay.


North Branch Potomac River

The source of the North Branch Potomac River is at the Fairfax Stone located at the junction of Grant, Tucker and Preston counties in West Virginia. From the Fairfax Stone, the North Branch Potomac River flows to the man-made Jennings Randolph Lake, an impoundment designed for flood control and emergency water supply. Below the dam, the North Branch cuts a serpentine path through the eastern Allegheny Mountains. First, it flows northeast by the communities of Bloomington, Luke, and Westernport in Maryland and then on by Keyser, West Virginia to
Cumberland Cumberland ( ) is an area of North West England which was historically a county. The county was bordered by Northumberland to the north-east, County Durham to the east, Westmorland to the south-east, Lancashire to the south, and the Scottish ...
, Maryland. At Cumberland, the river turns southeast. downstream from its source, the North Branch is joined by the South Branch between Green Spring and South Branch Depot, West Virginia from whence it flows past Hancock, Maryland and turns southeast once more on its way toward
Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...
, and the
Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Ea ...
.


South Branch Potomac River

The South Branch's source is northwest of Hightown along U.S. Route 250 on the eastern side of Lantz Mountain (3,934 ft) in Highland County, Virginia. From Hightown, the South Branch is a small meandering
stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...
that flows northeast along Blue Grass Valley Road through the communities of New Hampden and Blue Grass. At Forks of Waters, the South Branch joins with Strait Creek and flows north across the Virginia/West Virginia border into Pendleton County. The river then travels on a northeastern course along the western side of Jack Mountain (4,045 ft), followed by Sandy Ridge (2,297 ft) along U.S. Route 220. North of the confluence of the South Branch with Smith Creek, the river flows along Town Mountain (2,848 ft) around Franklin at the junction of U.S. Route 220 and U.S. Route 33. After Franklin, the South Branch continues north through the
Monongahela National Forest The Monongahela National Forest is a U.S. National Forest, national forest located in the Allegheny Mountains of eastern West Virginia, US. It protects over of federally managed land within a proclamation boundary that includes much of the Po ...
to Upper Tract where it joins with three sizeable streams: Reeds Creek, Mill Run, and Deer Run. Between Big Mountain (2,582 ft) and Cave Mountain (2,821 ft), the South Branch bends around the Eagle Rock (1,483 ft) outcrop and continues its flow northward into
Grant County Grant County may refer to: Places ;Australia * County of Grant, Victoria ;United States * Grant County, Arkansas * Grant County, Indiana * Grant County, Kansas *Grant County, Kentucky Grant County is a county located in the northern pa ...
. Into Grant, the South Branch follows the western side of Cave Mountain through the long Smoke Hole Canyon, until its confluence with the North Fork at Cabins, where it flows east to Petersburg. At Petersburg, the
South Branch Valley Railroad The South Branch Valley Railroad is a railroad in the Eastern Panhandle of West Virginia. The branch line, which parallels the South Branch Potomac River, runs north from Petersburg, West Virginia, Petersburg to Green Spring, West Virginia, Gre ...
begins, which parallels the river until its mouth at Green Spring. In its eastern course from Petersburg into Hardy County, the South Branch becomes more navigable allowing for
canoes A canoe is a lightweight, narrow water vessel, typically pointed at both ends and open on top, propelled by one or more seated or kneeling paddlers facing the direction of travel and using paddles. In British English, the term ''canoe'' ca ...
and smaller river vessels. The river splits and forms a series of large islands while it heads northeast to Moorefield. At Moorefield, the South Branch is joined by the South Fork South Branch Potomac River and runs north to Old Fields where it is fed by Anderson Run and Stony Run. At McNeill, the South Branch flows into
the Trough The Trough is a 6-mile long wooded gorge carved by the South Branch Potomac River (SBPR) and situated in the Allegheny Mountains of Hampshire and Hardy Counties, West Virginia, US. The area was the site of a 1756 skirmish of the French and In ...
where it is bound to its west by Mill Creek Mountain (2,119 ft) and to its east by Sawmill Ridge (1,644 ft). This area is the habitat to
bald eagles The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a Species complex, species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies ...
. The Trough passes into Hampshire County and ends at its confluence with Sawmill Run south of
Glebe A glebe (, also known as church furlong, rectory manor or parson's close(s)) is an area of land within an ecclesiastical parish used to support a parish priest. The land may be owned by the church, or its profits may be reserved to the church. ...
and Sector. The South Branch continues north parallel to South Branch River Road (
County Route A county highway (also county road or county route; usually abbreviated CH or CR) is a road in the United States and in the Canadian province of Ontario that is designated and/or maintained by the County (United States), county highway departm ...
8) toward Romney with a number of historic plantation farms adjoining it. En route to Romney, the river is fed by Buffalo Run, Mill Run, McDowell Run, and Mill Creek at Vanderlip. The South Branch is traversed by the Northwestern Turnpike (
U.S. Route 50 U.S. Route 50 or U.S. Highway 50 (US 50) is a major east–west route of the U.S. Highway system, stretching from Interstate 80 (I-80) in West Sacramento, California, to Maryland Route 528 (MD 528) in Ocean City, Maryland, on the Atlantic ...
) and joined by Sulphur Spring Run where it forms Valley View Island to the west of town. Flowing north of Romney, the river still follows the eastern side of Mill Creek Mountain until it creates a horseshoe bend at Wappocomo's
Hanging Rocks Hanging Rocks are perpendicular cliffs rising nearly above the Potomac River#South Branch Potomac River, South Branch Potomac River in Hampshire County, West Virginia, Hampshire County in the U.S. state of West Virginia. Hanging Rocks are locat ...
around the George W. Washington plantation, Ridgedale. To the west of Three Churches on the western side of South Branch Mountain, , the South Branch creates a series of bends and flows to the northeast by Springfield through Blue's Ford. After two additional horseshoe bends (meanders), the South Branch flows under the old
Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was the oldest railroads in North America, oldest railroad in the United States and the first steam engine, steam-operated common carrier. Construction of the line began in 1828, and it operated as B&O from 1830 ...
mainline between Green Spring and South Branch Depot, and joins the North Branch to form the Potomac.


Upper Potomac River

This stretch encompasses the section of the Potomac River from the
confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...
of its North and South Branches through Opequon Creek near
Shepherdstown, West Virginia Shepherdstown is a town in Jefferson County, West Virginia, United States, located in the lower Shenandoah Valley along the Potomac River. Home to Shepherd University, the town's population was 1,531 at the time of the 2020 census. The town wa ...
. Along the way the following tributaries drain into the Potomac:
North Branch Potomac River The North Branch Potomac River flows from Fairfax Stone in West Virginia to its confluence with the South Branch Potomac River near Green Spring, West Virginia, where it turns into the Potomac River proper. Course From the Fairfax Stone, th ...
,
South Branch Potomac River The South Branch Potomac River has its River source, headwaters in northwestern Highland County, Virginia, near Hightown, Virginia, Hightown along the eastern edge of the Allegheny Front. After a river distance of ,U.S. Geological Survey. Nationa ...
, Town Creek, Little Cacapon River, Sideling Hill Creek,
Cacapon River The Cacapon River ( ; meaning Medicine Waters), located in the Appalachian Mountains of West Virginia's eastern panhandle region, is an shallow river known for its fishing, boating, wildlife, hunting, and wilderness scenery. As part of the Potoma ...
, Sir Johns Run, Warm Spring Run, Tonoloway Creek, Fifteenmile Creek, Sleepy Creek, Cherry Run, Back Creek,
Conococheague Creek Conococheague Creek, a tributary of the Potomac River, is a free-flowing stream that originates in Pennsylvania and empties into the Potomac River near Williamsport, Maryland, Williamsport, Maryland. It is in length,U.S. Geological Survey. Natio ...
, and Opequon Creek.


Lower Potomac River

This section covers the Potomac from just above Harpers Ferry in West Virginia down to Little Falls, Maryland on the border between Maryland and Washington, DC. Along the way the following tributaries drain into the Potomac:
Antietam Creek Antietam Creek () is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the Potomac River located in south central Pennsylvania and western Maryland in the ...
,
Shenandoah River The Shenandoah River is the principal tributary of the Potomac River, long with two River fork, forks approximately long each,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August ...
, Catoctin Creek (Virginia),
Catoctin Creek (Maryland) Catoctin Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the Potomac River in Frederick County, Maryland, Frederick County, Maryland, US. Its s ...
, Tuscarora Creek, Monocacy River, Little Monocacy River, Broad Run, Goose Creek, Broad Run, Horsepen Branch, Little Seneca Creek, Tenmile Creek, Great Seneca Creek, Old Sugarland Run, Muddy Branch, Nichols Run, Watts Branch, Limekiln Branch, Carroll Branch, Pond Run, Clarks Branch, Mine Run Branch, Difficult Run, Bullneck Run, Rock Run, Scott Run, Dead Run, Turkey Run, Cabin John Creek, Minnehaha Branch, and Little Falls Branch.


Tidal Potomac River

The Tidal Potomac River lies below the
Fall Line A fall line (or fall zone) is the area where an upland region and a coastal plain meet and is noticeable especially the place rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the ...
. This 108-mile (174-km) stretch encompasses the Potomac from a short distance below the
Washington, DC Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and Federal district of the United States, federal district of the United States. The city is on the Potomac River, across from ...
- Montgomery County line, just downstream of the Little Falls of the Potomac River, to the
Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Ea ...
. Along the way the following tributaries drain into the Potomac: Pimmit Run, Gulf Branch, Donaldson Run,
Windy Run Windy Run is a small stream in Arlington County, Virginia. From its source near Lorcom Lane, Windy Run flows on a northeastern course and empties into the Potomac River within the Federal parklands of the George Washington Memorial Parkway.Coor ...
, Spout Run, Maddox Branch, Foundry Branch, Rock Creek, Rocky Run, Tiber Creek, Roaches Run, Washington Channel,
Anacostia River The Anacostia River is a river in the Mid-Atlantic states, Mid Atlantic region of the United States. It flows from Prince George's County, Maryland, Prince George's County in Maryland into Washington, D.C., where it joins with the Washington Ch ...
, Four Mile Run, Oxon Creek, Hunting Creek, Broad Creek, Henson Creek, Swan Creek, Piscataway Creek, Little Hunting Creek, Dogue Creek,
Accotink Creek Accotink Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary stream of the Potomac River in Fairfax County, Virginia, Fairfax County, Virginia, in the U ...
, Pohick Creek, Pomonkey Creek,
Occoquan River The Occoquan River is a tributary of the Potomac River in Northern Virginia, where it serves as part of the boundary between Fairfax and Prince William counties. The river is a scenic area, and several local high schools and colleges use the r ...
,
Neabsco Creek Neabsco Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 tributary of the lower tidal segment of the Potomac River in eastern Prince William County, Virginia. ...
, Powell's Creek, Mattawoman Creek, Chicamuxen Creek,
Quantico Creek Quantico Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 partially tidal tributary of the Potomac River in eastern Prince William County, Virginia. Quantico ...
, Little Creek,
Chopawamsic Creek Chopawamsic Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the Potomac River in Prince William and Stafford counties, Virginia. Chopawamsic Cre ...
, Tank Creek,
Aquia Creek Aquia Creek () is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the tidal segment of the Potomac River and is located in Northern Virginia. The creek's ...
,
Potomac Creek Potomac Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 tidal tributary of the Potomac River in King George and Stafford counties, Virginia. Potomac Creek's s ...
, Nanjemoy Creek, Chotank Creek, Port Tobacco River, Popes Creek, Gambo Creek, Clifton Creek, Piccowaxen Creek, Upper Machodoc Creek, Wicomico River, Cobb Island, Monroe Creek, Mattox Creek, Popes Creek, Breton Bay, Leonardtown, St. Marys River, Yeocomico River, Coan River, and Hull Creek.


History


Natural history

The river itself is at least 3.5 million years old, likely extending back ten to twenty million years before the present when the Atlantic Ocean lowered and exposed coastal sediments along the fall line. This included the area at Great Falls, which eroded into its present form during recent glaciation periods. The
stream gradient Stream gradient (or stream slope) is the grade (or slope) of a stream. It is measured by the ratio of drop in elevation and horizontal distance. It is a dimensionless quantity, usually expressed in units of meters per kilometer (m/km) or feet pe ...
of the entire river is 0.14%, a drop of 930 m over 652 km.


Human history

"Potomac" is a European spelling of '' Patawomeck'', the Algonquian name of a Native American village on its southern bank. Native Americans had different names for different parts of the river, calling the river above Great Falls ''Cohongarooton'', meaning "honking geese" and "Patawomke" below the Falls, meaning "river of swans". In 1608, Captain John Smith explored the river now known as the Potomac and made drawings of his observations which were later compiled into a map and published in London in 1612. This detail from that map shows his rendition of the river that the local tribes had told him was called the "Patawomeck". The spelling of the name has taken many forms over the years from " Patawomeck" (as on
Captain John Smith John Smith ( – 21 June 1631) was an English soldier, explorer, colonial governor, admiral of New England, and author. He was knighted for his services to Sigismund Báthory, Prince of Transylvania, and his friend Mózes Székely. Followin ...
's map) to "Patomake", "Patowmack", and numerous other variations in the 18th century and now "Potomac". The river's name was officially decided upon as "Potomac" by the Board on Geographic Names in 1931. The similarity of the name to the Ancient Greek word for river, ''potamos'', has been noted for more than two centuries but it appears to be due to chance. 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 The history of the present-day United States began in roughly 15,000 BC with the arrival of Peopling of the Americas, the first people in the Americas. In the late 15th century, European colonization of the Americas, European colonization beg ...
and American heritage has led to the Potomac being nicknamed "the Nation's River".
George Washington George Washington (, 1799) was a Founding Fathers of the United States, Founding Father and the first president of the United States, serving from 1789 to 1797. As commander of the Continental Army, Washington led Patriot (American Revoluti ...
, the first
President of the United States The president of the United States (POTUS) is the head of state and head of government of the United States. The president directs the Federal government of the United States#Executive branch, executive branch of the Federal government of t ...
, was born in, surveyed, and spent most of his life within, the Potomac basin. There is an apocryphal legend that Washington threw a silver dollar all the way across the river as a youth (even though the first silver dollar wasn't minted until five years before Washington's death) . All of Washington, D.C., the nation's
capital city A capital city, or just capital, is the municipality holding primary status in a country, state (polity), state, province, department (administrative division), department, or other administrative division, subnational division, usually as its ...
, also lies within the watershed. The First United States Congress by act of July 16, 1790 stated that the nation's capital was to be located on the river. The 1859 siege of Harper's Ferry at the river's
confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...
with the Shenandoah was a precursor to numerous epic battles of the
American Civil War The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of A ...
in and around the Potomac and its tributaries, such as the 1861
Battle of Ball's Bluff The Battle of Ball's Bluff (also known as the Battle of Leesburg or Battle of Harrison's Island) was an early battle of the American Civil War fought in Loudoun County, Virginia, on October 21, 1861, in which Union Army forces under Major Gener ...
and the 1862 Battle of Shepherdstown.General
Robert E. Lee Robert Edward Lee (January 19, 1807 – October 12, 1870) was a general officers in the Confederate States Army, Confederate general during the American Civil War, who was appointed the General in Chief of the Armies of the Confederate ...
crossed the river, thereby invading the North and threatening Washington, D.C., twice in campaigns climaxing in the battles of Antietam (September 17, 1862) and Gettysburg (July 1–3, 1863). Confederate General
Jubal Early Jubal Anderson Early (November 3, 1816 – March 2, 1894) was an American lawyer, politician and military officer who served in the Confederate States Army during the Civil War. Trained at the United States Military Academy, Early resigned his ...
crossed the river in July 1864 on his attempted raid on the nation's capital. The river not only divided the Union from the Confederacy, but also gave name to the Union's largest army, the
Army of the Potomac The Army of the Potomac was the primary field army of the Union army in the Eastern Theater of the American Civil War. It was created in July 1861 shortly after the First Battle of Bull Run and was disbanded in June 1865 following the Battle of ...
. The Patowmack Canal was intended by George Washington to connect the Tidewater region near Georgetown with
Cumberland Cumberland ( ) is an area of North West England which was historically a county. The county was bordered by Northumberland to the north-east, County Durham to the east, Westmorland to the south-east, Lancashire to the south, and the Scottish ...
, 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 Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface ...
in 1830. The
Chesapeake and Ohio Canal The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the Grand Old Ditch, operated from 1831 until 1924 along the Potomac River between Washington, D.C., and Cumberland, Maryland. It replaced the Patowmack 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 Rapids are sections of a river where the river bed has a relatively steep stream gradient, gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are needed for a rapid t ...
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 Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often (but not always) supplied through taps, in which case it is also calle ...
with the opening of the Washington Aqueduct in 1864, using a water intake constructed at Great Falls.Ways, Harry C. (1996). ''The Washington Aqueduct: 1852-1992.'' (Baltimore, MD: U.S. Army Corps of Engineers, Baltimore District)


Hydrology


Water supply and water quality

An average of approximately of water is withdrawn daily from the Potomac in the Washington area for
water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Th ...
, providing about 78 percent of the region's total water usage, this amount includes approximately 80 percent of the drinking water consumed by the region's estimated 6.1 million residents. As a result of damaging floods in 1936 and 1937, the Army Corps of Engineers proposed the Potomac River basin reservoir projects, a series of dams that were intended to regulate the river and to provide a more reliable water supply. One dam was to be built at Little Falls, just north of Washington, backing its pool up to Great Falls. Just above Great Falls, the much larger Seneca Dam was proposed whose reservoir would extend to Harpers Ferry. Several other dams were proposed for the Potomac and its tributaries. When detailed studies were issued by the Corps in the 1950s, they met sustained opposition, led by
U.S. Supreme Court The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all U.S. federal court cases, and over state court cases that turn on question ...
Justice
William O. Douglas William Orville Douglas (October 16, 1898January 19, 1980) was an American jurist who served as an associate justice of the Supreme Court of the United States from 1939 to 1975. Douglas was known for his strong progressive and civil libertari ...
, resulting in the plans' abandonment. The only dam project that did get built was Jennings Randolph Lake on the North Branch. The Corps built a supplementary water intake for the Washington Aqueduct at Little Falls in 1959.Scott, Pamela (2007)
"Capital Engineers: The U.S. Army Corps of Engineers in the Development of Washington, D.C., 1790–2004."
(Washington, DC: U.S. Army Corps of Engineers.) Publication No. EP 870-1-67. p. 256.
In 1940
Congress A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of ...
passed a law authorizing the creation of an
interstate compact In the United States, an interstate compact is a pact or agreement between two or more states, or between states and any foreign sub-national government. Description Most early interstate compacts resolved boundary disputes, but since the earl ...
to coordinate water quality management among states in the Potomac basin. Maryland, West Virginia, Pennsylvania, Virginia, and the District of Columbia agreed to establish the Interstate Commission on the Potomac River Basin. The compact was amended in 1970 to include coordination of water supply issues and land use issues related to water quality.ICPRB
"Potomac Timeline."
Updated 2008-04-15.
Beginning in the 19th century, with increasing
mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...
and
agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
upstream and urban
sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewerage, sewer system. Sewage consists of wastewater discharged fro ...
and runoff downstream, the
water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
of the Potomac River deteriorated. This created conditions of severe
eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...
. It is said that President
Abraham Lincoln Abraham Lincoln (February 12, 1809 – April 15, 1865) was the 16th president of the United States, serving from 1861 until Assassination of Abraham Lincoln, his assassination in 1865. He led the United States through the American Civil War ...
used to escape to the highlands on summer nights to escape the river's stench. In the 1960s, with dense green
algal Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, s ...
blooms covering the river's surface, President
Lyndon Johnson Lyndon Baines Johnson (; August 27, 1908January 22, 1973), also known as LBJ, was the 36th president of the United States, serving from 1963 to 1969. He became president after assassination of John F. Kennedy, the assassination of John F. Ken ...
declared the river "a national disgrace" and set in motion a long-term effort to reduce
pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
from
sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewerage, sewer system. Sewage consists of wastewater discharged fro ...
and restore the beauty and ecology of this historic river. One of the significant pollution control projects at the time was the expansion of the
Blue Plains Advanced Wastewater Treatment Plant Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C., is the largest Sewage_treatment#Tertiary_treatment, advanced wastewater treatment plant in the world. The facility is operated by the District of Columbia Water and Sewer Autho ...
, which serves Washington and several surrounding communities. Enactment of the 1972
Clean Water Act The Clean Water Act (CWA) is the primary federal law in the United States governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters; recognizing the primary respo ...
led to construction or expansion of additional
sewage treatment Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water p ...
plants in the Potomac watershed. Controls on
phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
, one of the principal contributors to eutrophication, were implemented in the 1980s, through sewage plant upgrades and restrictions on phosphorus in detergents. By the end of the 20th century, notable success had been achieved, as massive algal blooms vanished and recreational fishing and boating rebounded. Still, the aquatic
habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
of the Potomac River and its tributaries remain vulnerable to eutrophication,
heavy metals upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...
,
pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...
s and other toxic chemicals, over-fishing,
alien species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
, and
pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
s associated with fecal coliform
bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
and
shellfish Shellfish, in colloquial and fisheries usage, are exoskeleton-bearing Aquatic animal, aquatic invertebrates used as Human food, food, including various species of Mollusca, molluscs, crustaceans, and echinoderms. Although most kinds of shellfish ...
diseases. In 2005 two federal agencies, the
US Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March ...
and the
Fish and Wildlife Service A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fis ...
, began to identify fish in the Potomac and tributaries that exhibited "intersex" characteristics, as a result of endocrine disruption caused by some form of pollution. On November 13, 2007, the Potomac Conservancy, an environmental group, issued the river a grade of "D-plus", citing high levels of pollution and the reports of "
intersex Intersex people are those born with any of several sex characteristics, including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical binar ...
" fish. Since then, the river has improved with a reduction in nutrient runoff, return of fish populations, and land protection along the river. As a result, the same group issued a grade of "B" for 2017 and 2018. In March 2019, the Potomac Riverkeeper Network launched a laboratory boat dubbed the "Sea Dog", which will be monitoring water quality in the Potomac and providing reports to the public on a weekly basis; in that same month, the catching near Fletcher's Boat House of a
Striped Bass The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has ...
estimated to weigh was seen as a further indicator of the continuing improvement in the health of the river.


Discharge

The average daily flow during the
water year A water year (also called ''hydrological year'', ''discharge year'' or ''flow year'') is a term commonly used in hydrology to describe a time period of 12 months for which precipitation totals are measured. Its beginning differs from the calendar y ...
s 1931–2018 was  /s. The highest average daily flow ever recorded on the Potomac at Little Falls, Maryland (near Washington, D.C.), was in March 1936 when it reached  /s. The lowest average daily flow ever recorded at the same location was  /s in September 1966 The highest crest of the Potomac ever registered at Little Falls was 28.10 ft, on March 19, 1936; however, the most damaging flood to affect Washington, DC and its metropolitan area was that of October 1942.


Legal issues

For 400 years Maryland and Virginia have disputed control of the Potomac and its North Branch since both states' original
colonial charter A charter is a document that gives colonies the legal rights to exist. Charters can bestow certain rights on a town, city, university, or other institution. Colonial charters were approved when the king gave a grant of exclusive powers for the ...
s grant the entire river rather than half of it as is normally the case with boundary rivers. In its first state
constitution A constitution is the aggregate of fundamental principles or established precedents that constitute the legal basis of a polity, organization or other type of entity, and commonly determines how that entity is to be governed. When these pri ...
adopted in 1776, Virginia ceded its claim to the entire river but reserved free use of it, an act disputed by Maryland. Both states acceded to the 1785 Mount Vernon Compact and the 1877 Black-Jenkins Award which granted Maryland the river bank-to-bank from the low-water mark on the Virginia side while permitting Virginia full
riparian rights Riparian water rights (or simply riparian rights) is a system for allocating water among those who possess land along its path. It has its origins in English common law. riparian zone, Riparian water rights exist in many jurisdictions with a c ...
short of obstructing navigation. From 1957 to 1996, the Maryland Department of the Environment (MDE) routinely issued permits applied for by Virginia entities concerning the use of the Potomac. However, in 1996 the MDE denied a permit submitted by the Fairfax County Water Authority to build a water intake offshore, citing potential harm to Maryland's interests by an increase in Virginia sprawl caused by the project. After years of failed appeals within the Maryland government's appeal processes, in 2000 Virginia took the case to the
Supreme Court of the United States The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all Federal tribunals in the United States, U.S. federal court cases, and over Stat ...
, which exercises original jurisdiction in cases between two states. Maryland claimed Virginia lost its riparian rights by acquiescing to MDE's permit process for 63 years (MDE began its permit process in 1933). A
Special Master In the law of the United States, a special master is an official appointed by a judge to ensure judicial orders are followed, or in the alternative, to hear evidence on behalf of the judge and make recommendations to the judge as to the dispositi ...
appointed by the Supreme Court to investigate recommended the case be settled in favor of Virginia, citing the language in the 1785 Compact and the 1877 Award. On December 9, 2003, the Court agreed in a 7–2 decision. The original charters are silent as to which branch from the upper Potomac serves as the boundary, but this was settled by the 1785 Compact. When West Virginia seceded from Virginia in 1863, the question of West Virginia's succession in title to the lands between the branches of the river was raised, as well as title to the river itself. Claims by Maryland to West Virginia land north of the South Branch (all of
Mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
and Grant Counties and parts of
Hampshire Hampshire (, ; abbreviated to Hants.) is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Berkshire to the north, Surrey and West Sussex to the east, the Isle of Wight across the Solent to the south, ...
, Hardy, Tucker and Pendleton Counties) and by West Virginia to the Potomac's high-water mark were rejected by the Supreme Court in two separate decisions in 1910.


Fauna


Fish

A variety of fish inhabit the Potomac, including
bass Bass or Basses may refer to: Fish * Bass (fish), various saltwater and freshwater species Wood * Bass or basswood, the wood of the tilia americana tree Music * Bass (sound), describing low-frequency sound or one of several instruments in th ...
,
muskellunge The muskellunge (''Esox masquinongy''), often shortened to muskie, musky, ski, or lunge, is a species of large freshwater predatory fish native to North America. It is the largest member of the pike family, Esocidae. Origin of name The name ...
, pike,
walleye The walleye (''Sander vitreus'', Synonym (taxonomy), synonym ''Stizostedion vitreum''), also called the walleyed pike, yellow pike, yellow pikeperch or yellow pickerel, is a freshwater perciform fish native to most of Canada and to the Northern ...
. The northern snakehead, an invasive species resembling the native bowfin,
lamprey Lampreys (sometimes inaccurately called lamprey eels) are a group of Agnatha, jawless fish comprising the order (biology), order Petromyzontiformes , sole order in the Class (biology), class Petromyzontida. The adult lamprey is characterize ...
, and
American eel The American eel (''Anguilla rostrata'') is a facultative catadromous eel found on the eastern coast of North America. Anguillidae, Freshwater eels are fish belonging to the Elopomorpha, elopomorph superorder, a group of Phylogenetics, phylogen ...
, was first seen in 2004. Many species of sunfish are also present in the Potomac and its headwaters. Although rare,
bull shark The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in riv ...
s can be found. After having been depressed for many decades, the river's population of
American shad The American shad (''Alosa sapidissima'') is a species of anadromous clupeid fish naturally distributed on the North American coast of the North Atlantic, from Newfoundland to Florida, and as an introduced species on the North Pacific coast. T ...
is currently re-bounding as a result of the ICPRB's successful "American Shad Restoration Project" that was begun in 1995. In addition to stocking the river with more than 22 million shad fry, the Project supervised the construction of a fishway that was built to facilitate the passage of adults around the Little Falls Dam on the way to their traditional spawning grounds upstream.


Mammals

Early European colonists who settled along the Potomac found a diversity of large and small mammals living in the dense forests nearby.
Bison A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised. Of the two surviving species, the American ...
, elk, wolves (both
gray Grey (more frequent in British English) or gray (more frequent in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning that it has no chroma. It is the color of a cloud-covered s ...
and red) and
cougar The cougar (''Puma concolor'') (, ''Help:Pronunciation respelling key, KOO-gər''), also called puma, mountain lion, catamount and panther is a large small cat native to the Americas. It inhabits North America, North, Central America, Cent ...
s were still present at that time, but had been hunted to extirpation by the middle of the 19th century. Among the denizens of the Potomac's banks, beavers and otters met a similar fate, while small populations of American mink and American martens survived into the 20th century in some secluded areas. There is no record of early settlers having observed marine mammals in the Potomac, but several sightings of Atlantic bottle-nosed dolphins (''Tursiops truncatus'') were reported during the 19th century. In July 1844, a pod of 14 adults and young was followed up the river by men in boats as high as the Aqueduct Bridge (approximately the same location occupied by Key Bridge today). Since 2015, perhaps as a result of warmer temperatures, rising water levels in the Chesapeake Bay and improving water quality in the Potomac, unprecedented numbers of Atlantic bottle-nosed dolphins have been observed in the river. According to Dr. Janet Mann of Georgetown University'
Potomac-Chesapeake Dolphin Project
more than 500 individual members of the species have been identified in the Potomac during this period.


Birds


Reptiles


Amphibians


Additional images

File:South Branch Potomac River South Branch Depot WV 2004.JPG, The South Branch near
South Branch Depot, West Virginia South Branch Depot also known as South Branch is an Unincorporated area, unincorporated community in Hampshire County, West Virginia, Hampshire County in the U.S. state of West Virginia. Originally known as Forks of Potomac because of its proximit ...
File:View of Potomac River at Junction of Cacapon River.jpg, Confluence of the
Cacapon River The Cacapon River ( ; meaning Medicine Waters), located in the Appalachian Mountains of West Virginia's eastern panhandle region, is an shallow river known for its fishing, boating, wildlife, hunting, and wilderness scenery. As part of the Potoma ...
(barely visible) with the Potomac File:Potomac River Water Gaps Harpers Ferry w compass and pointer.jpg, Oblique air photo, facing southwest, of the Potomac River flowing through water gaps in the Blue Ridge Mountains. Virginia on the left, Maryland on the right, West Virginia in upper right, including Harpers Ferry (partially obscured by Maryland Heights of Elk Ridge Mountain) at the confluence of the Potomac and Shenandoah Rivers. File:Potomac River at Goose Creek.jpg, Potomac River at Goose Creek File:PR Great Falls of the Potomac aquatint by George Beck 1802.jpg, The Great Falls of the Potomac, viewed from the Virginia bank of the river (Engraving based on an aquatint drawn by George Jacob Beck in 1802)
File:Potomac River at Occonquan Bay.jpg, Potomac near Occoquan Bay File:PR Georgetown or City of Washington 1801 by Beck.jpg, View of the Potomac River, Analostan Island, Georgetown, and, in the distance, buildings of the nascent City of Washington. (Engraving based on an 1801 watercolor by George Jacob Beck.) File:Jefferson Memorial.jpg, Jefferson Memorial in
Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...
, viewed from across the Tidal Basin of the Potomac File:The Pentagon US Department of Defense building.jpg,
The Pentagon The Pentagon is the headquarters building of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C. The building was constructed on an accelerated schedule during World War II. As ...
, looking northeast with the Potomac in the distance File:East Branch of the Potomac 1839 (via xparency) LOC.jpg, East Branch of the Potomac (now called the
Anacostia River The Anacostia River is a river in the Mid-Atlantic states, Mid Atlantic region of the United States. It flows from Prince George's County, Maryland, Prince George's County in Maryland into Washington, D.C., where it joins with the Washington Ch ...
) near its confluence with the mainstem Potomac in Washington. (Watercolor drawn in 1839 by Augustus Kollner.) File:View of Potomac River from Mount Vernon.jpg, View of the Potomac from
Mount Vernon Mount Vernon is the former residence and plantation of George Washington, a Founding Father, commander of the Continental Army in the Revolutionary War, and the first president of the United States, and his wife, Martha. An American landmar ...
File:Potomac Reagan National.jpg, Potomac River seen while landing at Reagan National Airport
File:2016-06-06 16 55 09 View northeast down the North Branch Potomac River from the Gorman-Gormania Bridge (U.S. Route 50) between Gormania, Grant County, West Virginia and Gorman, Garrett County, Maryland.jpg, View northeast down the North Branch Potomac River from the Gorman-Gormania Bridge (U.S. Route 50) between Gormania, Grant County, West Virginia and Gorman, Garrett County, Maryland File:2016-06-18 07 22 42 View east down the North Branch Potomac River from the Piedmont-Westernport Bridge between Piedmont, Mineral County, West Virginia and Westernport, Allegany County, Maryland.jpg, The North Branch Potomac River near Piedmont, WV File:Potomac River South Branch Depot WV 2007 05 07 07.jpg, The South Branch Potomac River near South Branch Depot, WV File:South Branch Potomac River Millesons Mill WV 2007 05 07 01.jpg, The South Branch of the Potomac River at Millesons Mill, WV File:Map of Potomac River Watershed in West Virginia Virginia Pennsylvania Maryland.jpg, Potomac River Watershed in West Virginia, Virginia, Pennsylvania, and Maryland


See also

* List of cities and towns along the Potomac River * List of crossings of the Potomac River * List of islands on the Potomac River * List of rivers of Maryland * List of rivers of Virginia *
List of rivers of West Virginia This is a list of rivers in the U.S. state of West Virginia. List of West Virginia rivers includes streams formally designated as rivers. There are also smaller streams (i.e., branches, creeks, drains, forks, licks, runs, etc.) in the state. Exc ...
* List of tributaries of the Potomac River * List of variant names of the Potomac River * Potomac Heritage Trail *
Air Florida Flight 90 Air Florida Flight 90 was a scheduled domestic passenger flight operated from Washington National Airport (now Ronald Reagan Washington National Airport) to Fort Lauderdale–Hollywood International Airport, with an intermediate stopover at T ...
, a flight crashed into Potomac River just after takeoff from Washington National Airport * 2025 Potomac River mid-air collision, an American Eagle Bombardier CRJ701ER collided with a Sikorsky VH-60M Black Hawk, both crashed into Potomac River on January 29, 2025.


Notes and references


Notes

* * * * * *


References


Works cited

*Rice, James D., ''Nature and History in the Potomac Country: From Hunter-Gatherers to the Age of Jefferson.'' (2009), Baltimore: Johns Hopkins University Press; ; *Smith, J. Lawrence, ''The Potomac Naturalist: The Natural History of the Headwaters of the Historic Potomac'' (1968), Parsons, WV: McClain Printing Co.; ;


External links


Advanced Hydrologic Prediction Service

Baltimore/Washington (Sterling, VA)
- including Potomac River levels **Potomac River level a
Williamsport
**Potomac River level a
Harpers Ferry
{{Authority control Rivers of Washington, D.C. Rivers of Maryland Rivers of Virginia Rivers of West Virginia Monongahela National Forest History of West Virginia Borders of Maryland Borders of Virginia Borders of West Virginia American Heritage Rivers Tributaries of the Chesapeake Bay West Virginia placenames of Native American origin National Recreation Trails in Washington, D.C. National Recreation Trails in Maryland National Recreation Trails in Virginia National Recreation Trails in West Virginia