Westbrookville is a hamlet in the town of Deerpark in Orange County, New York, United States, along US 209. Westbrookville was named for Dirck Van Keuren Westbrook, an early settler. Fort Westbrook, dating back to the American Revolution, is extant. The 1900–1940 US Census lists it as part of Mamakating in Sullivan County. Situated between Port Jervis and Wurtsboro, it is close to the borders of Pennsylvania and New Jersey. Westbrookville is located within the Port Jervis City School District.