The City and County of San Francisco is the fourth most populous city in California and the 14th most populous city in the United States, with a 2007 estimated population of 764,976. One of the most densely populated major American cities, San Francisco is part of the much larger San Francisco Bay Area, which is home to approximately 7.2 million people. The city is located on the tip of the San Francisco Peninsula, with the Pacific Ocean to the west, San Francisco Bay to the east, and the Golden Gate to the north.

In 1776, the Spanish settled the tip of the peninsula, establishing a fort at the Golden Gate and a mission named for Francis of Assisi. The California Gold Rush in 1848 propelled the city into a period of rapid growth, transforming into the largest city on the West Coast of the United States at the time. After being devastated by the 1906 earthquake and fire, San Francisco was quickly rebuilt, hosting the Panama-Pacific International Exposition nine years later. During World War II, San Francisco was the send-off point for many soldiers to the Pacific Theater. After the war, the confluence of returning servicemen, massive immigration, liberalizing attitudes, and other factors gave rise to the Summer of Love and the gay rights movement, cementing San Francisco as a liberal bastion in the United States.

San Francisco is a popular international tourist destination famous for its landmarks, including the Golden Gate Bridge, Alcatraz Island, the cable cars, Coit Tower, and Chinatown, its steep rolling hills, and its eclectic mix of Victorian and modern architecture. The city is also known for its diverse, cosmopolitan population, including large and long-established Asian American and LGBT communities.