Sayville is a sub-unit of Wertheim National Wildlife Refuge. This sub-unit is located in West Sayville, New York, about two miles inland from the Great South Bay. It is the only land-locked refuge in the complex. Sayville consists primarily of oak-pitch pine forests interspersed with grasslands. This sub-unit support a diversity of migratory songbirds and raptors. The refuge contains the largest population of sandplain gerardia (a federally endangered plant) in the state of New York. Management activities focus on protecting and enhancing habitat for this endangered plant and for migratory birds.