Great River, New York is a suburban hamlet and CDP in the Town of Islip, Suffolk, USA situated approximately 50 miles east of NYC on South Shore of L.I., adjoining the Great South Bay, protected from the Atlantic Ocean by Fire Island.Great River's name derives from Connetquot, an Algonquian word for "Great River." Prior to the 1900s Great River was primarily home to wealthy families on mansion estates. As of the 2010 census, the population of Great River was 1,489.Great River's buildings include a New York City-style steak house in a turn of the century Public house, a delicatessen, a rural delivery post office and the Great River Fire Department.