The City and County of San Francisco is the fourth-largest city in California and the fourteenth-largest in the United States, with a 2005 population of 799,263. It is located on the tip of the San Francisco Peninsula and is the focal point of the San Francisco Bay Area, whose population is seven million. San Francisco is the second most densely populated major American city, after New York. The city is famous for its history in progressive social movements.

In 1776, the Spanish became the first Europeans to settle in San Francisco, which they named for St. Francis. With the advent of the California gold rush in 1848, and the Comstock Lode and silver mines in 1859, the city entered a period of rapid growth. After being devastated by the 1906 earthquake and fire, San Francisco was quickly rebuilt and is today one of the most recognizable cities in the United States.

San Francisco has a unique mix of physical characteristics, including its months-long episodes of fog, its steep rolling hills, its eclectic mix of architecture (including Victorian style houses and modern highrises), and its being bordered on three sides by the Pacific Ocean and the San Francisco Bay. Famous hallmarks and landmarks include the San Francisco cable cars, the Transamerica Pyramid, the Golden Gate Bridge and Alcatraz Island.