Great River is a suburban hamlet and CDP in the Town of Islip in Suffolk County, New York, United States. It is situated approximately 50 miles east of New York City on the South Shore of Long Island, adjoining the Great South Bay, protected from the Atlantic Ocean by Fire Island. Great River's name is a translation of "Connetquot," an Algonquian word for "Great River." Prior to the 1900s Great River was primarily home to wealthy families on mansion estates.