High Quality Content by WIKIPEDIA articles! The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates the San Francisco Bay from the Pacific Ocean. On its northern tip is the City and County of San Francisco. Its southern base is in Santa Clara County, including the cities of Palo Alto, Los Altos, and Mountain View. Most of the Peninsula is occupied by San Mateo County, between San Francisco and Santa Clara counties, and including the cities and towns of Atherton, Belmont, Brisbane, Burlingame, Colma, Daly City, East Palo Alto, El Granada, Foster City, Hillsborough, La Honda, Menlo Park, Millbrae, Montara, Pacifica, Pescadero, Portola Valley, Redwood City, San Bruno, San Carlos, San Gregorio, San Mateo, South San Francisco, and Woodside.