Delaware River

The Delaware River is a major river in the Mid-Atlantic region of the United States and is the longest free-flowing (undammed) river in the Eastern United States. From the meeting of its branches in Hancock, New York, the river flows for 282 miles (454 km) along the borders of New York, Pennsylvania, New Jersey, and Delaware, before emptying into Delaware Bay.

The river has been recognized by the National Wildlife Federation as one of the country's Great Waters and has been called the "Lifeblood of the Northeast" by American Rivers. Its watershed drains an area of 13,539 square miles (35,070 km²) and provides drinking water for 17 million people, including half of New York City via the Delaware Aqueduct.

The Delaware River has two branches that rise in the Catskill Mountains 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. Flowing south, the river remains relatively undeveloped, with 152 miles (245 km) protected as the Upper, Middle, and Lower Delaware National Scenic Rivers. At Trenton, New Jersey, the Delaware becomes tidal, navigable, and more industrial. This section forms the backbone of the Delaware Valley metropolitan area, serving the port cities of Philadelphia, Camden, New Jersey, and Wilmington, Delaware. The river flows into Delaware Bay at Liston Point, 48 miles (77 km) upstream of the bay's outlet to the Atlantic Ocean, between Cape May and Cape Henlopen.

Before the arrival of European settlers, the river was the homeland of the Lenape native people. They called the river Lënapei Sipu or Lenapewihittuk, meaning 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 expedition led by Henry Hudson, an English navigator hired to find a western route to Cathay (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. Both colonial powers called the river the South River (Zuidrivier), distinguishing it from the North River—today’s Hudson River. 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 in 1776 led victory in the Battle of Trenton, a pivotal moment in the American Revolution.

The Delaware River is named in honor of Thomas West, 3rd Baron De La Warr (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 after they had killed the colony's council president, John Ratcliffe, 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) is pronounced as in the current spelling form "Delaware" (/ˈdɛləwɛər/ ^ⓘ DEL-ə-wair) 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 expelled the Dutch 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 of Delaware was originally part of the William Penn's Pennsylvania colony. In 1682, the Duke of York 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 after the establishment of the United States.

The name "Delaware" also came to be used as a collective name for the Lenape, a Native American people who inhabited an area of the basins of the Susquehanna River, Delaware River, and lower Hudson River in the northeastern United States at the time of European settlement, as well as for their language. As a result of disruption following the French and Indian War, American Revolutionary War, 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. The Lenape refer to this river as the Lënapei Sipu, Lenapewihittuck, or Kithanna.