Brookhaven, formally the Town of Brookhaven, is a large suburban town in Suffolk County, Long Island, New York. With a population of 488,497 as of 2022, it is the second most populous town in the United States and in New York and the third most populous community in the state.

Suffolk County is the easternmost county in the U.S. state of New York. It is bordered to its west by Nassau County, to its east by Gardiners Bay and the Atlantic Ocean, to its north by Long Island Sound, and to its south by Great South Bay. The county is part of the Long Island region of the state, of which it comprises the eastern two-thirds.