Mendon Ponds Park is a county park located southeast of Rochester, New York within the suburban towns of Mendon and Pittsford. At over 2,500 acres (10 km2), it is the largest park in Monroe County. It was designated a National Natural Landmark in 1967 in recognition of its unique glacial geology. Monroe County acquired the first 1,400 acres of the park in 1928 for $185,000 (USD).