Rockland Lake, Hook Mountain, and Nyack Beach are located just 30 miles north of New York City. From the 1830s to 1930, the area was one of the largest producers of natural ice and was also the site of large traprock quarries. On the western side of Hook Mountain lies Rockland Lake, the only natural spring-fed lake entirely located in Rockland County. The lake was known around the world for its famous pure blue ice and was referred to as the ice box of New York City. In the 1910s, the area became a popular day-trip destination for steamboats from New York City and eventually became an active summer community in the 1920s. In 1965, the Palisades Interstate Park Commission opened Rockland Lake State Park. Today, the PIPC parks of Nyack Beach, Hook Mountain, and Rockland Lake are some of the most visited New York State parks.