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The Delaware River is a major
river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
in the Mid-Atlantic region of the United States and is the longest free-flowing (undammed) river in the
Eastern United States The Eastern United States, often abbreviated as simply the East, is a macroregion of the United States located to the east of the Mississippi River. It includes 17–26 states and Washington, D.C., the national capital. As of 2011, the Eastern ...
. From the meeting of its branches in
Hancock, New York Hancock is a town in Delaware County, New York, United States. The town contains a village, also named Hancock. The town is in the southwest part of the county. The population was 2,764 at the 2020 census. The town is the largest by area in De ...
, the river flows for along the borders of
New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...
,
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
,
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
, and
Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...
, before emptying into
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
. The river has been recognized by the
National Wildlife Federation The National Wildlife Federation (NWF) is the largest private, nonprofit conservation education and advocacy organization in the United States, with over six million members and supporters, and 51 state and territorial affiliated organizations (i ...
as one of the country's Great Waters and has been called the "Lifeblood of the Northeast" by
American Rivers American Rivers is a nonprofit environmental advocacy organization focused on protecting and promoting the health of rivers in the United States. Established in 1973, the group is headquartered in Washington, D.C. Activities River restoration A ...
. Its
watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...
drains an area of and provides drinking water for 17 million people, including half of
New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...
via the Delaware Aqueduct. The Delaware River has two branches that rise in the
Catskill Mountains The Catskill Mountains, also known as the Catskills, are a physiographic province and subrange of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined a ...
of New York: the West Branch at Mount Jefferson in Jefferson, Schoharie County, and the East Branch at Grand Gorge, Delaware County. The branches merge to form the main Delaware River at
Hancock, New York Hancock is a town in Delaware County, New York, United States. The town contains a village, also named Hancock. The town is in the southwest part of the county. The population was 2,764 at the 2020 census. The town is the largest by area in De ...
. Flowing south, the river remains relatively undeveloped, with protected as the Upper,
Middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ...
, and
Lower Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is sit ...
Delaware National Scenic Rivers. At
Trenton, New Jersey Trenton is the List of capitals in the United States, capital city of the U.S. state of New Jersey and the county seat of Mercer County, New Jersey, Mercer County. It was the federal capital, capital of the United States from November 1 until D ...
, the Delaware becomes tidal,
navigable A body of water, such as a river, canal or lake, is navigable if it is deep, wide and calm enough for a water vessel (e.g. boats) to pass safely. Navigability is also referred to in the broader context of a body of water having sufficient under ...
, and more industrial. This section forms the backbone of the
Delaware Valley The Philadelphia metropolitan area, also known as Greater Philadelphia and informally called the Delaware Valley, the Philadelphia tri-state area, and locally and colloquially Philly–Jersey–Delaware, is a major metropolitan area in the Nor ...
metropolitan area, serving the port cities of
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
,
Camden, New Jersey Camden is a City (New Jersey), city in Camden County, New Jersey, Camden County, in the U.S. state of New Jersey. It is part of the Delaware Valley metropolitan region. The city was incorporated on February 13, 1828.Snyder, John P''The Story of ...
, and
Wilmington, Delaware Wilmington is the List of municipalities in Delaware, most populous city in the U.S. state of Delaware. The city was built on the site of Fort Christina, the first Swedish colonization of the Americas, Swedish settlement in North America. It lie ...
. The river flows into
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
at Liston Point, upstream of the bay's outlet to the Atlantic Ocean, between
Cape May Cape May consists of a peninsula and barrier island system in the U.S. state of New Jersey. It is roughly coterminous with Cape May County and runs southwards from the New Jersey mainland, separating Delaware Bay from the Atlantic Ocean. Th ...
and
Cape Henlopen Cape Henlopen is the southern cape of the Delaware Bay along the Atlantic coast of the United States. It lies in the state of Delaware, near the town of Lewes, where the Delaware Bay meets the Atlantic Ocean. Off the coast on the bay side are two ...
. Before the arrival of European settlers, the river was the homeland of the
Lenape The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada. The Lenape's historica ...
native people. They called the river Lenapewihittuk, or Lenape River, and Kithanne, meaning the largest river in this part of the country. In 1609, the river was visited by a
Dutch East India Company The United East India Company ( ; VOC ), commonly known as the Dutch East India Company, was a chartered company, chartered trading company and one of the first joint-stock companies in the world. Established on 20 March 1602 by the States Ge ...
expedition led by
Henry Hudson Henry Hudson ( 1565 – disappeared 23 June 1611) was an English sea explorer and navigator during the early 17th century, best known for his explorations of present-day Canada and parts of the Northeastern United States. In 1607 and 16 ...
, an English navigator hired to find a western route to
Cathay Cathay ( ) is a historical name for China that was used in Europe. During the early modern period, the term ''Cathay'' initially evolved as a term referring to what is now Northern China, completely separate and distinct from ''China'', which w ...
(China). His encounters set the stage for Dutch colonization of North America in the 17th century. Early Dutch and Swedish settlements were established along the lower section of the river and
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
. Both
colonial powers Colonialism is the control of another territory, natural resources and people by a foreign group. Colonizers control the political and tribal power of the colonised territory. While frequently an imperialist project, colonialism can also take ...
called the river the ''South River'' (Zuidrivier), distinguishing it from the ''North River—''today’s
Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...
. After the English expelled the Dutch and took control of the New Netherland colony in 1664, the river was renamed ''Delaware'' after Sir Thomas West, 3rd Baron De La Warr, an English nobleman and the Virginia colony's first royal governor, who defended the colony during the First Anglo-Powhatan War.
George Washington's crossing of the Delaware River George Washington's crossing of the Delaware River, which occurred on the night of December 25–26, 1776, during the American Revolutionary War, was the first move in a complex and surprise military maneuver organized by George Washington, t ...
in 1776 led victory in the
Battle of Trenton The Battle of Trenton was a small but pivotal American Revolutionary War battle on the morning of December 26, 1776, in Trenton, New Jersey. After General George Washington's George Washington's crossing of the Delaware River, crossing of the ...
, a pivotal moment in the
American Revolution The American Revolution (1765–1783) was a colonial rebellion and war of independence in which the Thirteen Colonies broke from British America, British rule to form the United States of America. The revolution culminated in the American ...
.


Name

The Delaware River is named in honor of
Thomas West, 3rd Baron De La Warr Thomas West, 3rd Baron De La Warr ( ; 9 July 1576 – 7 June 1618), was an English nobleman, for whom the bay, the river, and, consequently, a Native American people and U.S. state, all later called "Delaware", were named. A member of the Ho ...
(1577–1618), an English nobleman and the Virginia colony's first royal governor, who defended the colony during the First Anglo-Powhatan War. Lord de la Warr waged a punitive campaign to subdue the
Powhatan Powhatan people () are Indigenous peoples of the Northeastern Woodlands who belong to member tribes of the Powhatan Confederacy, or Tsenacommacah. They are Algonquian peoples whose historic territories were in eastern Virginia. Their Powh ...
after they had killed the colony's council president,
John Ratcliffe John Lee Ratcliffe (born October 20, 1965) is an American politician and attorney who has served as the ninth director of the Central Intelligence Agency (CIA) since 2025. He previously served as the sixth director of national intelligence from ...
, and attacked the colony's fledgling settlements. Lord de la Warr arrived with 150 soldiers in time to prevent the colony's original settlers at Jamestown from giving up and returning to England and is credited with saving the Virginia colony. The name of the barony (later an
earldom Earl () is a rank of the nobility in the United Kingdom. In modern Britain, an earl is a member of the peerage, ranking below a marquess and above a viscount. A feminine form of ''earl'' never developed; instead, ''countess'' is used. The titl ...
) is pronounced as in the current spelling form "Delaware" ( ) and is thought to derive from French ''de la Guerre''. It has often been reported that the river and bay received the name "Delaware" after English forces under
Richard Nicolls Richard Nicolls ( – 28 May 1672) was an English military officer and colonial administrator who served as the first governor of the Province of New York from 1664 to 1668. Early life Richard Nicolls was born in in Ampthill, Bedfordshire. He ...
expelled the
Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...
and took control of the New Netherland colony in 1664. However, the river and bay were known by the name ''Delaware'' as early as 1641. The
state State most commonly refers to: * State (polity), a centralized political organization that regulates law and society within a territory **Sovereign state, a sovereign polity in international law, commonly referred to as a country **Nation state, a ...
of Delaware was originally part of the
William Penn William Penn ( – ) was an English writer, religious thinker, and influential Quakers, Quaker who founded the Province of Pennsylvania during the British colonization of the Americas, British colonial era. An advocate of democracy and religi ...
's Pennsylvania colony. In 1682, the
Duke of York Duke of York is a title of nobility in the Peerage of the United Kingdom. Since the 15th century, it has, when granted, usually been given to the second son of List of English monarchs, English (later List of British monarchs, British) monarchs ...
granted Penn's request for access to the sea and leased him the territory along the western shore of Delaware Bay, which became known as the "Lower Counties on the Delaware". In 1704, the Lower Counties were given political autonomy to form a separate provincial assembly, but they shared Pennsylvania's provincial governor until the two colonies separated on June 15, 1776, and they remained separate as
states State most commonly refers to: * State (polity), a centralized political organization that regulates law and society within a territory **Sovereign state, a sovereign polity in international law, commonly referred to as a country **Nation state, a ...
after the establishment of the United States. The name "Delaware" also came to be used as a collective name for the
Lenape The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada. The Lenape's historica ...
, a Native American people who inhabited an area of the basins of the
Susquehanna River The Susquehanna River ( ; Unami language, Lenape: ) is a major river located in the Mid-Atlantic (United States), Mid-Atlantic region of the United States, crossing three lower Northeastern United States, Northeast states (New York, Pennsylvani ...
, Delaware River, and lower
Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...
in the
northeastern United States The Northeastern United States (also referred to as the Northeast, the East Coast, or the American Northeast) is List of regions of the United States, census regions United States Census Bureau. Located on the East Coast of the United States, ...
at the time of European settlement, as well as for their
language Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed language, signed forms, and may also be conveyed through writing syste ...
. As a result of disruption following the
French and Indian War The French and Indian War, 1754 to 1763, was a colonial conflict in North America between Kingdom of Great Britain, Great Britain and Kingdom of France, France, along with their respective Native Americans in the United States, Native American ...
,
American Revolutionary War The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, was the armed conflict that comprised the final eight years of the broader American Revolution, in which Am ...
, and the later Indian removals from the eastern United States, the name "Delaware" has been spread with the Lenape's diaspora to municipalities, counties and other geographical features in the American Midwest and Canada.


Length

The length of the main stem of the Delaware River from the confluence of its branches to the head of
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
at Liston Point is . However, the river's tidal estuary widens gradually, and there is no clear hydrological dividing point between the river and the bay. Liston Point is considered the head of Delaware Bay only by legal agreement between New Jersey and Delaware, as marked by a pair of survey monuments. As such, some observers may include the entire length of Delaware Bay from Liston Point to the Atlantic Ocean in the length of the river, giving the Delaware River an overall length of . At either length the main stem of the Delaware River is the longest free-flowing river in the
Eastern United States The Eastern United States, often abbreviated as simply the East, is a macroregion of the United States located to the east of the Mississippi River. It includes 17–26 states and Washington, D.C., the national capital. As of 2011, the Eastern ...
. "Free-flowing" means the river is not impounded by dams and its course is not significantly altered or diverted. Idaho's Salmon River is the longest free-flowing river in the
contiguous United States The contiguous United States, also known as the U.S. mainland, officially referred to as the conterminous United States, consists of the 48 adjoining U.S. states and the District of Columbia of the United States in central North America. The te ...
, at . There are two
wing dam A wing dam or wing dike is a man-made barrier that, unlike a conventional dam, only extends partway into a river. These structures force water into a fast-moving center channel which reduces the rate of sediment accumulation, while slowing water f ...
s on the river, one between Lambertville and New Hope and one between Lumberville and Raven Rock. The wing dams affect the accumulation of sediment but do not cross the entire width of the river. Many tributaries of the Delaware River are dammed or diverted, including its two upper branches. Cannonsville Reservoir impounds the West Branch and
Pepacton Reservoir The Pepacton Reservoir is a reservoir in Delaware County, New York on the East Branch of the Delaware River in the Catskill Mountains of New York (state), New York. Part of the New York City water supply system, it was formed by the construction ...
impounds the East Branch, controlling the release of water in to the main stem Delaware River.


Watershed

The Delaware River's
drainage basin 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, ...
has an area of and encompasses 42 counties and 838 municipalities in five U.S. states: New York, New Jersey, Pennsylvania, Maryland, and Delaware.Philadelphia Water Department
"Moving from Assessment to Protection…The Delaware River Watershed Source Water Protection Plan" (PWSID #1510001)
(June 2007). Retrieved July 17, 2013.
This total area constitutes approximately 0.4% of the land mass in the United States. In 2001, the watershed was 18% agricultural land, 14% developed land, and 68% forested land. There are 216 tributary streams and creeks comprising an estimated 14,057 miles of streams and creeks, in the watershed. While the watershed is home to 4.17 million people according to the 2000 Federal Census, these bodies of water provide drinking water to 17 million people—roughly 6% of the population of the United States. The waters of the Delaware River's basin are used to sustain "fishing, transportation, power, cooling, recreation, and other industrial and residential purposes." It is the 33rd largest river in the United States in terms of flow, but is among the nation's most heavily used rivers in daily freight tonnage. The average annual flow rate of the Delaware is 11,700 cubic feet per second at
Trenton, New Jersey Trenton is the List of capitals in the United States, capital city of the U.S. state of New Jersey and the county seat of Mercer County, New Jersey, Mercer County. It was the federal capital, capital of the United States from November 1 until D ...
. With no dams or impediments on the river's main stem, the Delaware is one of the few remaining large free-flowing rivers in the United States. File:East Branch Delaware River at Margaretville, NY.jpg, East Branch of the Delaware River near Margaretville, New York File:Hawk's Nest view of DelawareR.jpg, Canoeing on the river at
Hawk's Nest (Orange County, New York) The Hawk's Nest is a scenic overlook high above the Delaware River on New York State Route 97. It is located in Deerpark, New York, Deerpark, Orange County, New York, Orange County, New York (state), New York, just northwest of Port Jervis, New ...
File:Delaware and Hudson Canal near Summitville, NY.jpg, A still remaining section of the
Delaware and Hudson Canal The Delaware and Hudson Canal was the first venture of the Delaware and Hudson Canal Company, which would later build the Delaware and Hudson Railway. Between 1828 and 1899, the canal's barges carried anthracite coal from the mines of northeast ...
seen from U.S. 209 near Summitville, New York File:Easton–Phillipsburg Toll Bridge, Dec 2021.jpg,
Easton–Phillipsburg Toll Bridge The Easton–Phillipsburg Toll Bridge is a modified Truss bridge#Pennsylvania (Petit) truss, Pennsylvania (Petit) through truss bridge that carries U.S. Route 22 over the Delaware River. The bridge is located between Easton, Pennsylvania and Ph ...
crosses the Delaware, connecting
Easton, Pennsylvania Easton is a city in and the county seat of Northampton County, Pennsylvania, United States. The city's population was 28,127 as of the 2020 United States census, 2020 census. Easton is located at the confluence of the Lehigh River and the Delawa ...
and
Phillipsburg, New Jersey Phillipsburg is a town located along the Delaware River that is the most populous municipality in Warren County, in the U.S. state of New Jersey. It is part of the Allentown-Bethlehem-Easton, PA-NJ metropolitan statistical area. As of the 202 ...
, in the
Lehigh Valley The Lehigh Valley () is a geography, geographic and urban area, metropolitan region formed by the Lehigh River in Lehigh County, Pennsylvania, Lehigh and Northampton County, Pennsylvania, Northampton counties in eastern Pennsylvania. It is a co ...
. File:BenjaminFranklinBridgeAtNight.jpg,
Benjamin Franklin Bridge The Benjamin Franklin Bridge, originally named the Delaware River Bridge and known locally as the Ben Franklin Bridge, is a suspension bridge across the Delaware River connecting Philadelphia, Pennsylvania, and Camden, New Jersey. Owned and ope ...
crosses the Delaware, connecting
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
and
Camden, New Jersey Camden is a City (New Jersey), city in Camden County, New Jersey, Camden County, in the U.S. state of New Jersey. It is part of the Delaware Valley metropolitan region. The city was incorporated on February 13, 1828.Snyder, John P''The Story of ...
. File:Walt Whitman Bridge at night.jpg,
Walt Whitman Bridge The Walt Whitman Bridge is a single-level suspension bridge spanning the Delaware River from Philadelphia in the west to Gloucester City in Camden County, New Jersey in the east. The bridge is named after American poet and essayist Walt Whi ...
crosses the Delaware, connecting
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
and
Gloucester City, New Jersey Gloucester City is a city in Camden County, in the U.S. state of New Jersey. As of the 2020 United States census, the city's population was 11,484, an increase of 28 (+0.2%) from the 2010 census count of 11,456, which in turn reflected a de ...
. File:DingmansFerryBridgeSide.jpg,
Dingman's Ferry Bridge The Dingman's Ferry Bridge (also known as the Dingmans Bridge) is a toll bridge across the Delaware River between Delaware Township, Pennsylvania and Sandyston Township, New Jersey. Owned and operated by the Dingmans Choice and Delaware Bri ...
connects
Sandyston Township, New Jersey Sandyston Township is a small rural Township (New Jersey), township in Sussex County, New Jersey, Sussex County, in the U.S. state of New Jersey. It is located in the northwestern part of the state near the Pennsylvania border. The township is s ...
, and Delaware Township in
Pike County, Pennsylvania Pike County is a County (United States), county in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States. As of the 2020 United States census, 2020 census, the population was 58,535. Its county seat is Milford, Pennsylvania ...
File:Delaware River DWG USA.jpg, The Delaware within the southern portion of the
Delaware Water Gap National Recreation Area The Delaware Water Gap National Recreation Area is a national recreation area administered by the National Park Service in northwest New Jersey and northeast Pennsylvania. It is centered around a stretch of the Delaware River designated the ...
, near Worthington State Forest in
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
File:2006 flood Westfall PA.png, A flood in Westfall, Pennsylvania, in 2006


Course


West Branch of the Delaware

The West Branch of the Delaware River, also called the Mohawk Branch, spans approximately from the northern
Catskill Mountains The Catskill Mountains, also known as the Catskills, are a physiographic province and subrange of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined a ...
to its
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 Delaware River's East Branch at
Hancock, New York Hancock is a town in Delaware County, New York, United States. The town contains a village, also named Hancock. The town is in the southwest part of the county. The population was 2,764 at the 2020 census. The town is the largest by area in De ...
. The last forms part of the boundary between New York and Pennsylvania. The West Branch rises in Schoharie County, New York at above sea level, near Mount Jefferson, and flows tortuously through the plateau in a deep trough. The branch flows generally southwest, entering Delaware County and flowing through the towns of Stamford and
Delhi Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, but spread chiefly to the west, or beyond its Bank (geography ...
. In southwestern Delaware County it flows in an increasingly winding course through the mountains, generally southwest. At Stilesville the West Branch was impounded in the 1960s to form the Cannonsville Reservoir, the westernmost of the reservoirs in the New York City water system. It is the most recently constructed New York City reservoir and began serving the city in 1964. Draining a large watershed of , the reservoir's capacity is . This water flows over halfway through the reservoir to enter the West Delaware Tunnel in Tompkins, New York. Then it flows through the aqueduct into the Rondout Reservoir, where the water enters the Delaware Aqueduct, that contributes to roughly 50% of the city's drinking water supply. At Deposit, on the border between Broome and Delaware counties, it turns sharply to the southeast and is paralleled by New York State Route 17. It joins the East Branch at above sea level at Hancock to form the Delaware.


East Branch of the Delaware

Similarly, the East Branch begins from a small pond south of Grand Gorge in the
town A town is a type of a human settlement, generally larger than a village but smaller than a city. The criteria for distinguishing a town vary globally, often depending on factors such as population size, economic character, administrative stat ...
of Roxbury in Delaware County, flowing southwest toward its impoundment by New York City to create the
Pepacton Reservoir The Pepacton Reservoir is a reservoir in Delaware County, New York on the East Branch of the Delaware River in the Catskill Mountains of New York (state), New York. Part of the New York City water supply system, it was formed by the construction ...
, the largest reservoir in the
New York City water supply system The New York City water supply system is a combination of Aqueduct (water supply), aqueducts, reservoirs, and tunnels which supplies fresh water to New York City. With three major water systems (New Croton Aqueduct, Croton, Catskill Aqueduct, Ca ...
. Its tributaries are the Beaver Kill River and the Willowemoc Creek which enter into the river before the West Branch meets the East Branch. The confluence of the two branches is just south of Hancock. The East Branch and West Branch of the Delaware River parallel each other, both flowing in a southwesterly direction.


Upper Delaware Valley

From
Hancock, New York Hancock is a town in Delaware County, New York, United States. The town contains a village, also named Hancock. The town is in the southwest part of the county. The population was 2,764 at the 2020 census. The town is the largest by area in De ...
, the Delaware flows between the northern Poconos in Pennsylvania, and the lowered shale beds north of the Catskills. The river flows down a broad Appalachian valley, passing Hawk's Nest overlook on the Upper Delaware Scenic Byway. The river flows southeast for 78 miles through rural regions along the New York-Pennsylvania border to Port Jervis and
Shawangunk Ridge The Shawangunk Ridge , also known as the Shawangunk Mountains or The Gunks, is a ridge of bedrock in Ulster County, Sullivan County and Orange County in the state of New York, extending from the northernmost point of the border with New Jers ...
.


The Minisink

At
Port Jervis Port Jervis, named after John Bloomfield Jervis, a Roman civil engineer who oversaw the construction of the Delaware and Hudson Canal, is a city located at the confluence of the Neversink and Delaware rivers in western Orange County, New York, ...
, New York, it enters the Port Jervis trough. At this point, the Walpack Ridge deflects the Delaware into the Minisink Valley, where it follows the southwest
strike Strike may refer to: People *Strike (surname) * Hobart Huson, author of several drug related books Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm * Airstrike, ...
of the eroded
Marcellus Formation The Marcellus Formation or the Marcellus Shale is a Middle Devonian age unit of sedimentary rock found in eastern North America. Named for a distinctive outcrop near the village of Marcellus, New York, it extends throughout much of the Appalac ...
beds A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...
along the Pennsylvania–New Jersey state line for to the end of the ridge at Walpack Bend in the
Delaware Water Gap National Recreation Area The Delaware Water Gap National Recreation Area is a national recreation area administered by the National Park Service in northwest New Jersey and northeast Pennsylvania. It is centered around a stretch of the Delaware River designated the ...
. The Minisink is a buried valley where the Delaware flows in a bed of
glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
that buried the eroded bedrock during the last glacial period. It then skirts the Kittatinny ridge, which it crosses at the
Delaware Water Gap The Delaware Water Gap is a water gap on the border of the U.S. states of New Jersey and Pennsylvania where the Delaware River cuts through a large ridge of the Appalachian Mountains. The gap makes up the southern portion of the Delaware Wa ...
, between nearly vertical walls of
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
,
quartzite Quartzite is a hard, non- foliated metamorphic rock that was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...
, and conglomerate, and then passes through a quiet and charming country of farm and forest, diversified with plateaus and escarpments, until it crosses the Appalachian plain and enters the hills again at Easton, Pennsylvania. From this point it is flanked at intervals by fine hills, and in places by cliffs, of which the finest are the Nockamixon Cliffs, long and above high. The
Appalachian Trail The Appalachian Trail, also called the A.T., is a hiking trail in the Eastern United States, extending almost between Springer Mountain in Georgia and Mount Katahdin in Maine, and passing through 14 states.Gailey, Chris (2006)"Appalachian Tra ...
, which traverses the ridge of Kittatinny Mountain in New Jersey, and Blue Mountain in Pennsylvania, crosses the Delaware River at the Delaware Water Gap near Columbia, New Jersey.


Central Delaware Valley

In
Easton, Pennsylvania Easton is a city in and the county seat of Northampton County, Pennsylvania, United States. The city's population was 28,127 as of the 2020 United States census, 2020 census. Easton is located at the confluence of the Lehigh River and the Delawa ...
, the
Lehigh River The Lehigh River () is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 1, 2011 tributary of the Delaware River in eastern Pennsylvania. The river flows in a generally southward ...
joins the Delaware. At Trenton, the Delaware crosses the Atlantic Seaboard Fall Line with a drop of .


Lower Delaware and Tidewater

Below Trenton, the Delaware flows between
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
and
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
before becoming a broad, sluggish inlet of the sea, with many marshes along its side, widening steadily into its great estuary,
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
. The Delaware River constitutes the boundary between Delaware and New Jersey. The Delaware–New Jersey border is actually at the easternmost river shoreline within the Twelve-Mile Circle of New Castle, rather than at mid-river, mid-channel or
thalweg In geography, hydrography, and fluvial geomorphology, a thalweg or talweg () is the line or curve of lowest elevation within a valley or watercourse. Normally only the horizontal position of the curve is considered (as viewed on a map); the c ...
, so small portions of land lying west of the shoreline, but on the New Jersey side of the river, are
pene-exclave An enclave is a territory that is entirely surrounded by the territory of only one other state or entity. An enclave can be an independent territory or part of a larger one. Enclaves may also exist within territorial waters. ''Enclave'' is s ...
s under the jurisdiction of Delaware. The rest of the borders follow a mid-channel approach.


History

At the time of the arrival of the
Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
ans in the early 17th century, the area near the Delaware River was inhabited by the Native American
Lenape The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada. The Lenape's historica ...
people. They called the Delaware River "Lenape Wihittuck", which means "the rapid stream of the Lenape".Delaware Place Names
United States 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 Mar ...
The Delaware River played a key factor in the economic and social development of the Mid-Atlantic region. In the seventeenth century it provided the conduit for colonial settlement by the
Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...
(
New Netherland New Netherland () was a colony of the Dutch Republic located on the East Coast of what is now the United States. The claimed territories extended from the Delmarva Peninsula to Cape Cod. Settlements were established in what became the states ...
) and the Swedish (
New Sweden New Sweden () was a colony of the Swedish Empire between 1638 and 1655 along the lower reaches of the Delaware River in what is now Delaware, Maryland, New Jersey, and Pennsylvania. Established during the Thirty Years' War when Sweden was a g ...
). Beginning in 1664, the region became an English possession as settlement by Quakers established the colonies of
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
(including present-day
Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...
) and
West Jersey West Jersey and East Jersey were two distinct parts of the Province of New Jersey. The political division existed for 28 years, between 1674 and 1702. Determination of an exact location for a border between West Jersey and East Jersey was often ...
. In the eighteenth century, cities like
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
, Camden (then Cooper's Ferry), Trenton, Wilmington and New Castle were established upon the Delaware and their continued commercial success into the present day has been dependent on access to the river for trade and power. The river provided the path for the settlement of northeastern Pennsylvania's
Lehigh Valley The Lehigh Valley () is a geography, geographic and urban area, metropolitan region formed by the Lehigh River in Lehigh County, Pennsylvania, Lehigh and Northampton County, Pennsylvania, Northampton counties in eastern Pennsylvania. It is a co ...
, and northwestern New Jersey by German Palatine immigrants—a population that became key in the agricultural development of the region.


Swedish Colonization (1638–1655)

In 1638, Swedish settlers, led by Peter Menuet, established New Sweden along the Delaware River. This settlement marked one of the earliest European establishments in the region, with Fort Christina (located near modern-day Wilmington, Delaware) becoming a key trading post and symbol of Swedish colonial ambition. The Swedes engaged in peaceful land negotiations with the local Lenape people and developed a thriving colony. New Sweden became a center for trade and cultural exchange between the Swedish settlers, Native Americans, and neighboring Dutch colonies. Although the Dutch would later assert dominance over the region in 1655, New Sweden laid the groundwork for European settlement along the Delaware River. The fort and surrounding settlements played a crucial role in the early European rivalry for control of North America's resources and territory. This era of Swedish colonization is an important part of the Delaware River's history, adding to its diverse cultural legacy.


American Revolutionary War

The strategic Delaware River was the scene of several important campaigns during the
American Revolutionary War The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, was the armed conflict that comprised the final eight years of the broader American Revolution, in which Am ...
. Perhaps the most famous event was
George Washington's crossing of the Delaware River George Washington's crossing of the Delaware River, which occurred on the night of December 25–26, 1776, during the American Revolutionary War, was the first move in a complex and surprise military maneuver organized by George Washington, t ...
with the
Continental Army The Continental Army was the army of the United Colonies representing the Thirteen Colonies and later the United States during the American Revolutionary War. It was formed on June 14, 1775, by a resolution passed by the Second Continental Co ...
on the night of December 25–26, 1776, leading to a successful surprise attack and victory against the Hessian troops occupying
Trenton, New Jersey Trenton is the List of capitals in the United States, capital city of the U.S. state of New Jersey and the county seat of Mercer County, New Jersey, Mercer County. It was the federal capital, capital of the United States from November 1 until D ...
, on the morning of December 26. During the
Philadelphia Campaign The Philadelphia campaign (1777–1778) was a British military campaign during the American Revolutionary War designed to gain control of Philadelphia, the Revolutionary-era capital where the Second Continental Congress convened, formed the ...
control of the Delaware River was urgently needed by the British, allowing their naval fleet to supply troops occupying Philadelphia. To this end, the
Battle of Red Bank The Battle of Red Bank, also known as the Battle of Fort Mercer, was fought on October 22, 1777, during the American Revolutionary War. A British and Hessian force was sent to take Fort Mercer on the New Jersey side of the Delaware River just s ...
and the Siege of Fort Mifflin were fought on and along the shores of the Delaware by the American and British navies, commanded by Commodore John Hazelwood and Admiral Francis Reynolds respectively. See historical map of that campaign.


Canals

The magnitude of the commerce of
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
has made the improvements of the river below that port of great importance. Small improvements were attempted by
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
as early as 1771. Commerce was once important on the upper river, primarily prior to railway competition of 1857. * The Delaware Division of the Pennsylvania Canal, running parallel with the river from Easton to Bristol, opened in 1830. * The
Delaware and Raritan Canal The Delaware and Raritan Canal (D&R Canal) is a canal in central New Jersey, built in the 1830s, that connects the Delaware River to the Raritan River. It was an efficient and reliable means of transportation of freight between Philadelphia and ...
, which runs along the New Jersey side of the Delaware River from Bulls Island, New Jersey to Trenton, unites the waters of the Delaware and Raritan rivers as it empties the waters of the Delaware River via the canal outlet in
New Brunswick New Brunswick is a Provinces and Territories of Canada, province of Canada, bordering Quebec to the north, Nova Scotia to the east, the Gulf of Saint Lawrence to the northeast, the Bay of Fundy to the southeast, and the U.S. state of Maine to ...
. This canal water conduit is still used as a water supply source by the State of
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
. * The
Morris Canal The Morris Canal (1829–1924) was a toll road, common carrier Anthracite, anthracite coal canal across North Jersey, northern New Jersey that connected the two industrial canals in Easton, Pennsylvania across the Delaware River from its weste ...
(now abandoned and almost completely filled in) and the
Delaware and Hudson Canal The Delaware and Hudson Canal was the first venture of the Delaware and Hudson Canal Company, which would later build the Delaware and Hudson Railway. Between 1828 and 1899, the canal's barges carried anthracite coal from the mines of northeast ...
connected the Delaware and Hudson rivers. * The
Chesapeake and Delaware Canal The Chesapeake & Delaware Canal (C&D Canal) is a -long, -wide and -deep ship canal that connects the Delaware River with the Chesapeake Bay in the states of Delaware and Maryland in the United States. In the mid-17th century, mapmaker Augus ...
joins the waters of the Delaware with those of 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 ...
.


Delaware Water Gap National Recreation Area

The
Delaware Water Gap National Recreation Area The Delaware Water Gap National Recreation Area is a national recreation area administered by the National Park Service in northwest New Jersey and northeast Pennsylvania. It is centered around a stretch of the Delaware River designated the ...
came about as a result of the failure of a controversial plan to build a dam on the Delaware River at Tocks Island, just north of the
Delaware Water Gap The Delaware Water Gap is a water gap on the border of the U.S. states of New Jersey and Pennsylvania where the Delaware River cuts through a large ridge of the Appalachian Mountains. The gap makes up the southern portion of the Delaware Wa ...
to control water levels for flood control and hydroelectric power generation. The dam would have created a lake in the center of present park for use as a reservoir. Starting in 1960, the present-day area of the Recreation Area was acquired for the Army Corps of Engineers through
eminent domain Eminent domain, also known as land acquisition, compulsory purchase, resumption, resumption/compulsory acquisition, or expropriation, is the compulsory acquisition of private property for public use. It does not include the power to take and t ...
. Between 3,000 and 5,000 dwellings were demolished, including historical sites, and about 15,000 people were displaced by the project. Because of massive environmental opposition, dwindling funds, and an unacceptable geological assessment of the dam's safety, the government transferred the property to the
National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...
in 1978. The National Park Service found itself as the caretaker of the previously endangered territory, and with the help of the federal government and surrounding communities, developed recreational facilities and worked to preserve the remaining historical structures. The nearby Shawnee Inn,Squeri, p. 182. was identified in the 1990s as the only resort along the banks of the Delaware River.
American Rivers American Rivers is a nonprofit environmental advocacy organization focused on protecting and promoting the health of rivers in the United States. Established in 1973, the group is headquartered in Washington, D.C. Activities River restoration A ...
, an environmental advocacy group, named the Delaware River as the River of the Year for 2020, citing 75 years of progress in reducing pollution and restoring wildlife.


Commerce


Wine regions

In 1984, the
U.S. Department of the Treasury The Department of the Treasury (USDT) is the national treasury and finance department of the federal government of the United States. It is one of 15 current U.S. government departments. The department oversees the Bureau of Engraving and ...
authorized the creation of a wine region or "
American Viticultural Area An American Viticultural Area (AVA) is a designated wine grape-growing region in the United States, providing an official appellation for the mutual benefit of winery, wineries and consumers. Winemakers frequently want their consumers to know abo ...
" called the Central Delaware Valley AVA located in southeastern
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
and
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
. The
wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
appellation An appellation is a legally defined and protected geographical indication used to identify where the ingredients of a food or beverage originated, most often used for the origin of wine grapes. Restrictions other than geographical boundaries, s ...
includes surrounding the Delaware River north of
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
and Trenton, New Jersey. In Pennsylvania, it consists of the territory along the Delaware River in
Bucks County Bucks County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 646,538, making it the fourth-most populous county in Pennsylvania. Its county seat is Doylestown. The county is named after the English ...
; in New Jersey, the AVA spans along the river in
Hunterdon County Hunterdon County is a County (United States), county located in the western section of the U.S. state of New Jersey. At the 2020 United States census, 2020 census, the county was the state's List of counties in New Jersey, 4th-least populous ...
and Mercer County from Titusville, New Jersey, just north of Trenton, northward to
Musconetcong Mountain Musconetcong Mountain is a ridge in the Highlands region of New Jersey running south of and parallel to the Musconetcong River. The ridge travels through Alexandria, Holland, Bethlehem and Lebanon Township. Prominent Features *Point Mountain, 9 ...
.Code of Federal Regulations
Section 9.49 Central Delaware Valley.
(27 CFR 9.49) from ''Title 27 - Alcohol, Tobacco Products and Firearms. CHAPTER I - ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY. SUBCHAPTER A - LIQUORS. PART 9 - AMERICAN VITICULTURAL AREAS. Subpart C - Approved American Viticultural Areas.'' Retrieved June 30, 2013.
As of 2013, there are no
New Jersey wine New Jersey wine refers to wine made from grapes grown in the state of New Jersey. Its viticulture industry has significantly grown since 1981 when the state legislature relaxed Prohibition-era restrictions and enacted new laws to provide furthe ...
ries in the Central Delaware Valley AVA.


Shipping

In the Project of 1885, the U.S. government systematically undertook the formation of a deep federal navigation shipping channel wide from
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
to into
Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...
. The River and Harbor Act of 1899 provided for a channel wide from Philadelphia to the deep water of the bay. Since 1941, the Delaware River Main Channel was maintained at a depth of . Since 2013 there has been a push to deepen the 102.5-mile stretch from Philadelphia and Camden to the mouth of the Delaware Bay to 45 feet.U.S. Army Corps of Engineers.
Delaware River Main Channel Deepening Project
''. (May 2012). Retrieved July 14, 2013.
The Delaware River port complex refers to the ports and energy facilities along the river in the tri-state PA- NJ- DE
Delaware Valley The Philadelphia metropolitan area, also known as Greater Philadelphia and informally called the Delaware Valley, the Philadelphia tri-state area, and locally and colloquially Philly–Jersey–Delaware, is a major metropolitan area in the Nor ...
region. They include the Port of Salem, the Port of Wilmington, the Port of Chester, the Port of Paulsboro, the
Port of Philadelphia The port of Philadelphia is located on the Delaware River in Philadelphia in the U.S. state of Pennsylvania. ''Port of Philadelphia'' generally refers to the publicly owned marine terminals located within Philadelphia city limits along the west b ...
and the Port of Camden. Combined they create one of the largest shipping areas of the United States. In 2015, the ports of Philadelphia, Camden, and Wilmington handled 100 million tons of cargo from 2,243 ship arrivals, and supported 135,000 direct or indirect jobs. The biggest category of imports was fruit, carried by 490 ships, followed by petroleum, and containers, with 410 and 381 ships, respectively. The biggest category of exports was of shipping was containers, with 470 ships. In 2016, 2,427 ships arrived at Delaware River port facilities. Fruit ships were counted at 577, petroleum at 474, and containerized cargo at 431. At one time it was a center for petroleum and chemical products and included facilities such as the Delaware City Refinery, the Dupont Chambers Works, Oceanport Terminal at Claymont, the Marcus Hook Refinery, the
Trainer Refinery Trainer Refinery is an oil refinery located in Trainer, Pennsylvania. The facility is downstream from the Port of Chester and fifteen miles southwest of Philadelphia along the Delaware River. Stoney Creek is along its northern perimeter. The ...
, the Paulsboro Asphalt Refinery, Paulsboro Refinery, Eagle Point Refinery, and Sunoco Fort Mifflin. As of 2011,
crude oil Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...
was the largest single commodity transported on the Delaware River, accounting for half of all annual cargo tonnage.


Crossings

The Delaware River is a major barrier to travel between
New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
and
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
. Most of the larger bridges are tolled only westbound, and are owned by the
Delaware River and Bay Authority The Delaware River and Bay Authority (DRBA) is a bi-state government agency of the United States, U.S. states of Delaware and New Jersey established by an interstate compact in 1962. The authority operates the Delaware Memorial Bridge, Delaw ...
,
Delaware River Port Authority The Delaware River Port Authority (DRPA), officially the Delaware River Port Authority of Pennsylvania and New Jersey, is a bi-state agency instrumentality created by a congressionally approved interstate compact between the state governments ...
,
Burlington County Bridge Commission The Burlington County Bridge Commission is a public agency responsible for the operation and maintenance of several bridges in Burlington County, New Jersey, United States, across the Delaware River. It now manages eight bridges, including the Ta ...
or
Delaware River Joint Toll Bridge Commission The Delaware River Joint Toll Bridge Commission (DRJTBC) is a bistate, public agency that maintains and operates river crossings connecting the U.S. states of Pennsylvania and New Jersey. The agency's jurisdiction stretches roughly along the D ...
.


Environmental issues


New York City water supply

After
New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...
built 15 reservoirs to supply water to the city's growing population, it was unable to obtain permission to build an additional five reservoirs along the Delaware River's tributaries. As a result, in 1928 the city proposed to draw water from the Delaware River, putting them in direct conflict with villages and towns across the river in
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
which were already using the Delaware for their water supply. Additionally, the
Government of New Jersey The government of the State of New Jersey is separated into three distinct branches: legislature, legislative, executive (government), executive, and judiciary, judicial. The powers of the State of New Jersey are vested by the Constitution of ...
raised concerns that New York's water diversions might hinder New Jersey's future development of dams and
hydropower Hydropower (from Ancient Greek -, "water"), also known as water power or water energy, is the use of falling or fast-running water to Electricity generation, produce electricity or to power machines. This is achieved by energy transformation, ...
; that 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 river would be impacted, due to reduced flows of fresh water; and that its
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 ...
would be diminished. New Jersey filed suit against New York State and New York City, with the
Government of Pennsylvania The Government of the Commonwealth of Pennsylvania is the governmental structure of the Commonwealth of Pennsylvania as established by the Pennsylvania Constitution. It is composed of three branches: Executive (government), executive, Legislatur ...
intervening in the case to protect its interests. In 1931 the
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 ...
decided that New York could draw water from the Delaware tributaries, subject to the laws of
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 ...
and regulation by the
US Army Corps of Engineers The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil wor ...
. New York City was allowed to draw of water a day from the Delaware and its upstream tributaries, going on to build three large reservoirs and the Delaware Aqueduct they feed.


Pollution

The Delaware River has been attached to areas of high
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 ...
. The Delaware River in 2012 was named the 5th most polluted river in the United States, explained by PennEnvironment and Environment New Jersey. The activist groups claim that there is about 7–10 million pounds of toxic chemicals flowing through the waterways due to dumping by DuPont Chambers Works. PennEnvironment also claims that the pollutants in the river can cause birth defects, infertility among women, and have been linked to cancer. In 2015, the EPA saw the Delaware River as a concern for mass pollution especially in the Greater Philadelphia and Chester, Pennsylvania area. The EPA was involved after accusations that the river met standards made illegal by the
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 ...
. In complying with the Clean Water Act, the EPA involved the Delaware County Regional Water Authority (DELCORA) where they set up a plan to spend around $200 million to help rid the waterway of about 740 million gallons of sewage and pollution. DELCORA was also fined about $1.4 million for allowing the Delaware River to have so much pollution residing in the river in the first place and for not complying with the Clean Water Act. Part of the Clean Water Act explains how conditions of the river should be stable enough for human fishing and swimming. Even though the river has had success with the cleanup of pollution, the Delaware River still does not meet that standard of swimmable or fishable conditions in the Philadelphia/Chester region. In March 2023, a pipe rupture at a Trinseo chemical plant in
Bristol, Pennsylvania Bristol is a borough (Pennsylvania), borough in Bucks County, Pennsylvania, United States. It is located northeast of Center City, Philadelphia, Center City in Philadelphia opposite Burlington, New Jersey, on the Delaware River. Bristol was s ...
, released over 8,000 gallons of
latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...
finishing material into the Otter Creek tributary, leading to a water advisory in
Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
.


Flooding

With the failure of the dam project to come to fruition, the lack of flood control on the river left it vulnerable, and it has experienced a number of serious flooding events as the result of snow melt or rain run-off from heavy rainstorms. Record flooding occurred in August 1955, in the aftermath of the passing of the remnants of two separate hurricanes over the area within less than a week: first
Hurricane Connie Hurricane Connie was a Category 4 hurricane that contributed to significant flooding across the eastern United States in August 1955, just days before Hurricane Diane affected the same general area. Connie formed on August 3 from a tropica ...
and then
Hurricane Diane Hurricane Diane was the first Atlantic hurricane to cause more than an estimated $1 billion in damage (in 1955 dollars, which would be $11,764,962,686 today), including direct costs and the loss of business and personal revenue. It tropical ...
, which was, and still is, the wettest tropical cyclone to have hit the northeastern United States. The river gauge at Riegelsville, Pennsylvania recorded an all-time record crest of on August 19, 1955. More recently, moderate to severe flooding has occurred along the river. The same gauge at Riegelsville recorded a peak of on September 23, 2004, on April 4, 2005, and on June 28, 2006, all considerably higher than the flood stage of . Since the upper Delaware basin has few population centers along its banks, flooding in this area mainly affects natural unpopulated flood plains. Residents in the middle part of the Delaware basin experience flooding, including three major floods in the three years (2004–2006) that have severely damaged their homes and land. The lower part of the Delaware basin from Philadelphia southward to the Delaware Bay is tidal and much wider than portions further north, and is not prone to river-related flooding (although tidal surges can cause minor flooding in this area). The
Delaware River Basin Commission The Delaware River Basin Commission (DRBC) is a United States government agency created in 1961 by an interstate compact, signed into law by President John F. Kennedy, between four states (Pennsylvania, Delaware, New Jersey, and New York (state ...
, along with local governments, is working to try to address the issue of flooding along the river. As the past few years have seen a rise in catastrophic floods, most residents of the river basin feel that something must be done. The local governments have worked in association with FEMA to address many of these problems, however, due to insufficient federal funds, progress is slow.


Oil spills

A number of
oil spill An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s have taken place in the Delaware over the years. * January 31, 1975: around of crude oil spilled from the ''Corinthos'' tanker * September 28, 1985: of crude oil spilled from the ''Grand Eagle'' tanker after running aground on Marcus Hook Bar * June 24, 1989: of crude oil spilled from the ''Presidente Rivera'' tanker after running aground on
Claymont Shoal Claymont is a census-designated place (CDP) in New Castle County, Delaware, United States. As of the 2020 U.S. census, the population of Claymont was 9,895. History The community now known as Claymont started on the banks of Naamans Creek where ...
* November 26, 2004: of crude oil spilled from the ''Athos 1'' tanker; the tanker's hull had been punctured by a submerged, discarded anchor at the Port of Paulsboro. In 2020, the Supreme Court ruled that
Citgo Citgo Petroleum Corporation, or Citgo (stylized as CITGO), is a United States–based refiner, transporter and marketer of transportation fuels, lubricants, petrochemicals and other industrial products. Headquartered in the Energy Corridor area ...
had failed to provide a safe berth for the vessel and was therefore jointly responsible for clean up costs. The company was ordered to pay $143 million.


Atlantic sturgeon

The
National Marine Fisheries Service The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the ste ...
is considering designating sixteen rivers as endangered habitat for the
Atlantic sturgeon The Atlantic sturgeon (''Acipenser oxyrinchus'') is a large species of sturgeon native to both sides of the Atlantic Ocean, and associated river basins. It is a member of the family Acipenseridae, and, along with other sturgeon, it is sometimes ...
which would require more attention to be given to uses of the rivers that affect the fish.


National Wild and Scenic River

The river is part of the
National Wild and Scenic Rivers System The National Wild and Scenic Rivers System was created by the Wild and Scenic Rivers Act of 1968 (Public Law 90-542), enacted by the U.S. Congress to preserve certain rivers with outstanding natural, cultural, and recreational values in a free- ...
.


See also

*
Geography of Pennsylvania The geography of Pennsylvania varies from sea level marine estuary to mountainous plateau. The state is known for its natural resources, ports, and the leading role it played in the founding and history of the United States. Major features Pen ...
* List of municipalities on the Delaware River *
List of crossings of the Delaware River This is a list of bridges, ferries, and other crossings of the Delaware River and Delaware Bay from the Atlantic Ocean upstream to the confluence of the East Branch Delaware River, East Branch and West Branch Delaware River, West Branch at Hancoc ...
*
List of rivers of Delaware List of rivers in Delaware (U.S. state), grouped by type and sorted by name. Major rivers and creeks (28) *Appoquinimink River * Blackbird Creek * Brandywine Creek * Broad Creek * Broadkill River *Choptank River *Christina River *Delaware River ...
*
List of rivers of New Jersey This is a list of streams and rivers of the U.S. state of New Jersey. The list of New Jersey rivers includes streams formally designated as rivers, as well as smaller streams such as branches, creeks, drains, forks, licks, runs, etc. found throu ...
*
List of rivers of New York Rivers in the U.S. state of New York include: By drainage basin This list is arranged by drainage basin, with tributaries indented by order of confluence, from mouth to source. New York Harbor Block Island Sound *Peconic River ** Little Rive ...
*
List of rivers of Pennsylvania This is a list of streams and rivers in the U.S. state of Pennsylvania. By drainage basin This list is arranged by drainage basin, with respective tributaries indented under each larger stream's name. Delaware Bay Chesapeake Bay *''E ...
*
List of most-polluted rivers This list contains rivers and other 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 ...
* Partnership for the Delaware Estuary *
Upper Delaware Scenic and Recreational River The Upper Delaware Scenic and Recreational River is a unit of the National Park Service designated under the National Wild and Scenic Rivers System. It stretches along of the Delaware River between Hancock, New York, and Sparrowbush, New York. ...


Citations


General and cited references

*
Devastation on the Delaware: Stories and Images of the Deadly Flood of 1955
(2005
Word Forge Books
, Ferndale, PA) The only comprehensive documentary of this weather disaster in the Delaware River Valley. * * *


External links


Delaware Riverkeeper Network

Delaware River Basin Commission

Delaware River Vessel Reporting System


* ttps://www.nps.gov/upde/index.htm National Park Service: Upper Delaware Scenic & Recreational River
National Park Service: Lower Delaware Wild & Scenic River

U.S. Geological Survey: NJ stream gaging stations

U.S. Geological Survey: NY stream gaging stations

U.S. Geological Survey: PA stream gaging stations

Early Americas Digital Archive


Historical content


Marine Railway and Sectional Floating Dry Dock, Delaware River, Philadelphia, 1893 by D.J. Kennedy, Historical Society of Pennsylvania

Winter on the River Delaware, 1856. Shows "U.S.S. Powhatan" by D.J. Kennedy, HSP

"Map of the South River in New Netherland"
from c. 1639 via the
World Digital Library The World Digital Library (WDL) is an international digital library operated by UNESCO and the United States Library of Congress. The WDL has stated that its mission is to promote international and intercultural understanding, expand the volume ...

Socioeconomic Value of the Delaware River Basin in Delaware, New Jersey, New York, and Pennsylvania


Encyclopedias

* * * {{Authority control Borders of Delaware Borders of Maryland Borders of New Jersey Borders of New York (state) Borders of Pennsylvania Catskill/Delaware watersheds Delaware Valley Delaware Water Gap National Recreation Area Rivers of Bucks County, Pennsylvania Rivers of Burlington County, New Jersey Rivers of Camden County, New Jersey Rivers of Delaware Rivers of Delaware County, New York Rivers of Gloucester County, New Jersey Rivers of Hunterdon County, New Jersey Rivers of Maryland Rivers of Mercer County, New Jersey Rivers of Monroe County, Pennsylvania Rivers of New Castle County, Delaware Rivers of New Jersey Rivers of New York (state) Rivers of Orange County, New York Rivers of Pennsylvania Rivers of Philadelphia Rivers of Pike County, Pennsylvania Rivers of Salem County, New Jersey Rivers of Sullivan County, New York Rivers of Wayne County, Pennsylvania Rivers of Delaware County, Pennsylvania Rivers of Northampton County, Pennsylvania Rivers of Sussex County, New Jersey Rivers of Warren County, New Jersey Wild and Scenic Rivers of the United States