Grahamsville is a hamlet at the junction of NY 42 and 55 in the Town of Neversink, in Sullivan County, New York, United States. It is near the western end of Rondout Reservoir, and is the southernmost community in the Catskill Park. It has the ZIP Code 12740 and the 985 telephone exchange in the 845 area code. Grahamsville is located at latitude 41.848 and longitude-74.548. The elevation is 968 feet. Grahamsville is in the Eastern Time Zone.