The Town of Oyster Bay is the easternmost of the three towns which make up Nassau County, New York, in the United States. Part of the New York metropolitan area, it is the only town in Nassau County to extend from the North Shore to the South Shore of Long Island. As of the 2010 census, it had a population of 293,214.
There are 18 villages and 18 hamlets within the town of Oyster Bay. The U.S. Postal Service has organized these 36 places into 30 different five-digit ZIP Codes served by 20 different post offices. Each post office shares the name of one of the hamlets or villages, but their boundaries are usually not coterminous.
Oyster Bay is also the name of a hamlet on the north shore, within the town of Oyster Bay. Near this hamlet, in the village of Cove Neck, is Sagamore Hill, the former residence and summer White House of Theodore Roosevelt and now a museum. At least six of the 36 villages and hamlets of the town have shores on Oyster Bay Harbor, an inlet of Long Island Sound, and many of these at one time or another have also been referred to as being part of the hamlet of Oyster Bay.