San Francisco is in California.
San Francisco . Located at the north end of the San Francisco Peninsula , San Francisco is about 47.9 sqmi in area , making it the smallest county -- and the only consolidated city-county -- within the state of California . The San Francisco Bay Area ( referred to locally as the Bay Area ) is a populous region surrounding the San Francisco and San Pablo estuaries in Northern California . The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates San Francisco Bay from the Pacific Ocean .