Wallkill is a hamlet, generally identified as coterminous with ZIP Code 12589, telephone exchange 895 in the 845 area code and most of the Wallkill Central School District located mostly in the eastern half of the town of Shawangunk, Ulster County, New York, United States, but partly spilling over into adjacent regions of the Orange County towns of Newburgh and Montgomery. The population was 2,166 at the 2020 census. The Wallkill and Shawangunk correctional facilities are located in Wallkill.