Black Mountain is a summit on Monte Bello Ridge in the Santa Cruz Mountains of west Santa Clara County, California, south of Los Altos and Los Altos Hills, and west of Cupertino; it is within the Palo Alto city limits though not near the developed part of the city. It is located on the border between Rancho San Antonio Open Space Preserve and Monte Bello Open Space Preserve, with the summit located in the former.