Rockland Lake State Park is a 1,133-acre (4.59 km2) state park located in the hamlets of Congers and Valley Cottage in the eastern part of the Town of Clarkstown in Rockland County, New York. The park is located on a ridge of Hook Mountain above the west bank of the Hudson River. Included within the park is the 256-acre (1.04 km2) Rockland Lake.Development of the park as part of the Palisades Interstate Park system began in 1958. Rockland Lake State Park is functionally part of a continuous complex of parks that also includes Hook Mountain State Park, Nyack Beach State Park, and Haverstraw Beach State Park.