Jones Beach Island is a barrier island off the southern coast of Long Island in the U.S. state of New York. It is named for the father of historian Thomas Jones. It is sometimes referred to as Oak Beach Island, and the former home of the infamous Oak Beach Inn. It is separated from Long Island by Great South Bay. The island straddles the county line between Nassau and Suffolk counties and includes the census-designated places of Gilgo and Oak Beach–Captree, New York.