Delaware

River flowing through the states of New York, Pennsylvania, New Jersey, and Delaware; length 650 km/450 mi. It serves as a state boundary along much of its course. The river is an important source of hydroelectric power for the Northeast.

The main branch rises in Schoharie, New York, then flows southwards through Appalachian valleys and across plateaux before cutting through hills again at Easton, and meeting the sea at Trenton, New Jersey. Along its course are also Port Jervis, Philadelphia, Chester, and Wilmington. The river is controlled by an interstate commission. Dredging has helped river traffic.

It was explored by Henry Hudson in 1609, and its first European settlements were Dutch and Swedish. The river's name, from Lord de la Warr, governor of Virginia in 1610, was also to be applied to the area's native inhabitants, the Lenni Lenape (or Delaware).