Connetquot River

The Connetquot River (also known as Great River) is a 6 mi (10 km) long river in Islip. It is one of the four biggest rivers on Long Island and is recognized by the state as a Wild, Scenic and Recreational River. It is particularly known for its brook, brown and rainbow trout fly fishing.

The upper reaches of the river including its headwaters are totally in the Connetquot River State Park Preserve or Lakeland County Park before it becomes an estuary. It starts just south of the Long Island Expressway from springs in the Lakeland County Park in Islandia, New York where it is called Connetquot Brook. The estuary portion south of Sunrise Highway at Oakdale, New York is officially called the Connetquot River although in popular usage both the brook and river share the same name.

The name comes from the Secatogue tribe name for "Great River" and is different from the Carmans River on Long Island which at one time was called the Connecticut River.

The Connetquot River habitat is the largest contiguous area of undeveloped land in Suffolk County that encompasses an entire river watershed. It, like all other rivers on Long Island, is totally generated from groundwater springs (no lakes).