San Francisco isn't a place in California.
Golden Gate Bridge . The structure links the American city of San Francisco , California -- the northern tip of the San Francisco Peninsula -- to Marin County , carrying both U.S. Route 101 and California State Route 1 across the strait . San Francisco ( initials SF ) ( [ sæn_frənˈsɪskoʊ ] , Spanish for Saint Francis ; Spanish : [ san franˈsisko ] ) , officially the City and County of San Francisco , is the cultural , commercial , and financial center of Northern California . San Francisco is the fourth-most populous city in California , after Los Angeles , San Diego , and San Jose , and the 13th-most populous city in the United States -- with a census-estimated 2016 population of 870,887 . A popular tourist destination , San Francisco is known for its cool summers , fog , steep rolling hills , eclectic mix of architecture , and landmarks , including the Golden Gate Bridge , cable cars , the former Alcatraz Federal Penitentiary , Fisherman 's Wharf , and its Chinatown district . 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 .