High Quality Content by WIKIPEDIA articles! Clarkstown is a town in Rockland County, New York, United States. The town is on the eastern border of the county, located north of the town of Orangetown; east of the town of Ramapo; South of the town of Haverstraw and west of the Hudson River. As of the 2000 census, the town had a total population of 82,082. The community of New City in the town is the seat of town government and of the Clarkstown Police Department, county sherriff`s police office, and correctional facility. New City makes up about 41.47% of the town`s population.