the city and county of san francisco is generally placed in a category by itself in terms of geography and culture. it is separated by water from the north, west and east, and by a county line from its neighbors to the south. san francisco has been the cultural, financial and urban center of the region for a long time. for most of the bay area's history, it has also been the main population center. but because the size of the county is limited, the growth of the city was limited as well. the resulting urban sprawl has given other cities and counties more population growth.