San Francisco downtown skyline at dusk, shot from Alamo Park.

San Francisco, officially the City and County of San Francisco, is the cultural center and a leading financial hub of the San Francisco Bay Area and Northern California.

The only consolidated city-county in California, San Francisco encompasses a land area of about 46.9 square miles on the northern end of the San Francisco Peninsula, giving it a density of about 17,867 people per square mile. It is the most densely settled large city (population greater than 200,000) in the state of 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 14th-most populous city in the United States—with a Census-estimated 2013 population of 837,442. The city is also the financial and cultural hub of the larger San Jose-San Francisco-Oakland combined statistical area, with a population of 8.5 million.

San Francisco is a popular tourist destination, known for its cool summers, fog, steep rolling hills, eclectic mix of architecture, and landmarks including the Golden Gate Bridge, cable cars, the former prison on Alcatraz Island, and its Chinatown district. San Francisco is also the headquarters of five major banking institutions and various other companies.