San Francisco, offeecially the Ceety an Coonty o San Francisco, is the fowert maist populous ceety in Californie an the 12t maist populous ceety in the Unitit States, wi a 2009 estimatit population o 815,358. The anerlie consolidated ceety-coonty in Californie, it encompasses a land aurie o 46.7 square miles on the northren end o the San Francisco Peninsula, givin it a density o 17,323 fowk/mi². It is the maist densely settled lairge ceety in the state o Californie an the seicont-maist densely populatit lairge ceety in the Unitit States. San Francisco is the financial, cultural, an transportation centre o the San Francisco Bay Area, a region o mair nor 7.4 million fowk which includes San Jose an Oakland.