West Nyack is a hamlet and census-designated place in the town of Clarkstown, Rockland County, New York, United States. It is located north of Blauvelt, east of Nanuet, southwest of Valley Cottage, southeast of Bardonia, and west of Central Nyack. It is approximately 18 miles (29 km) north of New York City. The population was 3,439 at the 2010 census.

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 2020 census, the town had a total population of 86,855. The hamlet 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 office, and the county correctional facility. New City makes up about 41.47% of the town's population.