High Quality Content by WIKIPEDIA articles! Bridgeville is a hamlet southeast of Monticello, New York (the county seat) located in the southern Catskill Mountains in the Town of Thompson, County of Sullivan, and State of New York, U.S.A. Bridgeville is located on the Neversink River on New York State Route 17 (future Interstate 86), at an elevation of 1,081 feet (329 m). It has hilly terrain.