East River

East River
East River (foreground) and the headquarters of the United Nations in Manhattan (background) seen from Roosevelt Island in December 2006
Aerial map of New York City with the East River shown in red
Location
Country	United States
State	New York
Municipality	New York City
Physical characteristics
Source	Long Island Sound
• coordinates	40°48′00″N 73°47′06″W / 40.800°N 73.785°W / 40.800; -73.785
Mouth	Upper New York Bay
• coordinates	40°42′00″N 74°00′18″W / 40.700°N 74.005°W / 40.700; -74.005
Length	16 mi (26 km)
Basin features
Tributaries
• left	Newtown Creek, Flushing River
• right	Westchester Creek, Bronx River, Bronx Kill, Harlem River

The East River is a saltwater tidal estuary or strait in New York City. The waterway, which is not a river despite its name, connects Upper New York Bay on its south end to Long Island Sound on its north end. It separates Long Island, with the boroughs of Brooklyn and Queens, from Manhattan Island, and from the Bronx on the North American mainland. The East River forms the eastern boundary of Manhattan Island, whereas the island's western boundary is formed by the Hudson River.^[1]

Because of its connection to Long Island Sound, it was once also known as the Sound River.^[2] The tidal strait changes its direction of flow regularly, and is subject to strong fluctuations in its current, which are accentuated by its narrowness and variety of depths. The waterway is navigable for its entire length of 16 miles (26 km), and was historically the center of maritime activities in the city.^[1][3]