The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates San Francisco Bay from the Pacific Ocean. On its northern tip is the City and County of San Francisco. Its southern base is Los Altos and Mountain View, in Santa Clara County, south of Palo Alto and north of Sunnyvale. Most of the Peninsula is occupied by San M…The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates San Francisco Bay from the Pacific Ocean. On its northern tip is the City and County of San Francisco. Its southern base is Los Altos and Mountain View, in Santa Clara County, south of Palo Alto and north of Sunnyvale. 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, Half Moon Bay, Hillsborough, La Honda, Loma Mar, Los Altos, Los Altos Hills, Menlo Park, Millbrae, Mountain View, Pacifica, Palo Alto, Pescadero, Portola Valley, Redwood City, Redwood Shores, San Bruno, San Carlos, San Mateo, South San Francisco, West Menlo Park and Woodside.