There is a city called San Francisco.
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 . 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 . With a density of about 18,581 people per square mile ( 7,174 people per km2 ) , San Francisco is the most densely settled large city ( population greater than 200,000 ) in California and the second-most densely populated major city in the United States after New York City . 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 . The California Gold Rush of 1849 brought rapid growth , making it the largest city on the West Coast at the time .