According to the United States Census Bureau, the town has a total area of 133.9 square miles (346.7 km²), of which, 130.8 square miles (338.6 km²) of it is land and 3.1 square miles (8.1 km²) of it (2.32%) is water. The western and southern borders of the town is Sullivan County, New York. The northern part of the town is the southern-most portion of the Catskill Mountains. The eastern border is the Shawangunk Ridge (pronounced Shaw-ong-ungk). Rondout Creek passes through the town, as do the Sandburgh, Laurenkill, Beerkill, Fantinekill and Ver Nooy kill creeks.