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 2010 census, the town had a total population of 84,187. The community of New City, the county seat of Rockland County, is also the seat of town government and of the Clarkstown Police Department, the county sheriff's police office, and the county correctional facility. New City makes up about 41.47% of the town's population.