Near the western edge of Rockland County rise the craggy foothills of the Ramapo Mountains. At nearly 600 million years old, the Precambrian Ramapos—which spill over into New Jersey—are one of the oldest land masses in North America. At one time, their slopes—now eroded and dotted with erratics left during the Ice Age—constituted a mountain system as grand as the Rockies.

In New York, most of the Ramapos fall within two very popular state parks—Harriman and Bear Mountain. The parks were created largely through the efforts of Mrs. E. H. Harriman, widow of the railroad tycoon Edward Harriman and mother of the late statesman W. Averell Harriman.

When the state proposed building a prison at Bear Mountain in 1908, Mrs. Harriman offered to give the Palisades Interstate Park Commission 10,000 acres in return for dropping the project. The proposal was accepted and since then the parks have been significantly enlarged through other gifts and purchases.