The Santa Cruz Mountains, part of the Pacific Coast Ranges, are a mountain range in central and northern California, United States. They form a ridge down the San Francisco Peninsula, south of San Francisco. They separate the Pacific Ocean from the San Francisco Bay and the Santa Clara Valley, and continue south to the Central Coast, bordering Monterey Bay and ending at the Salinas Valley. The range passes through the counties of San Mateo, Santa Clara, Santa Cruz, San Benito and Monterey, with the Pajaro River forming the southern boundary.