The Pepacton Reservoir, also known as the Downsville Reservoir or the Downsville Dam, is a reservoir in Delaware County, New York that was formed by impounding over ¼ of the East Branch of the Delaware River. New York City purchased the valley in 1942, displacing 974 people, destroying four towns (Arena, Pepacton, Shavertown and Union Grove), and submerging nearly ½ of the Delaware and Northern Railroad in the process.