Nissequogue River
General data
- Name: Nissequogue River
- Water system: Atlantic Ocean
- Water type: River
- Progression: Long Island Sound -> Atlantic Ocean -> Planet Earth
- Climates: Temperate
- Continents: North America
- Countries: United States of America
The Nissequogue River is an 8.3-mile (13.4 km) long river flowing from Smithtown, New York into the Long Island Sound.
Its average discharge of 42.2 cubic feet per second (1.19 m3/s) is the most of any of the freshwater rivers on Long Island. The river, like all other freshwater rivers on the island, is totally derived from groundwater (not from lakes).