San Francisco, officially the City and County of San Francisco, is the 17th-largest city and second-densest major city in the United States, with a 2025 population of 826,079. It is the fourth-most populous city in California and the second most-populous in the Bay Area. Some 4.6 million residents live in the city's metropolitan statistical area. Around 9.2 million live in the San Jose–San Francisco–Oakland combined statistical area, the fifth-largest in the United States. San Francisco is a global center for technology and finance, and is well-known for its affluence, eclectic architecture, and mild climate.
Prior to European settlement, San Francisco was inhabited by the Yelamu Ohlone. On June 29, 1776, settlers from New Spain established the Presidio of San Francisco at the Golden Gate, and the Mission San Francisco de Asís a few miles away, both named for Francis of Assisi. The California gold rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time. In 1856, San Francisco became a consolidated city-county. After three-quarters of the city was destroyed by the 1906 earthquake and fire, it was quickly rebuilt, hosting the Panama–Pacific International Exposition nine years later. In World War II, it was a major port of embarkation for naval service members shipping out to the Pacific theater. After the war, the confluence of returning servicemen, significant immigration, liberalizing attitudes, the rise of the beatnik and hippie countercultures, the sexual revolution, opposition to U.S. involvement in the Vietnam War, and other factors led to the Summer of Love and the gay rights movement, cementing San Francisco as a center of liberal activism.
In 2024, San Francisco had a GDP of $268 billion and a GDP per capita of $324,000, ranking first by per capita income and sixth by aggregate income among U.S. cities with a population of 300,000 or more. The city's productivity is spurred by its leading universities, and by its high-tech, healthcare, finance, insurance, real estate, and professional services sectors. The city is home to numerous companies—many in the technology sector—including Salesforce, Uber, Airbnb, Levi's, Gap, OpenAI, Chime, Anthropic, Databricks, Dropbox, and Lyft.
In 2022, San Francisco had more than 1.7 million international visitors and approximately 20 million domestic visitors. It is known for its steep rolling hills, varied neighborhoods (including Chinatown and the Mission District); and landmarks including the Golden Gate Bridge, cable cars, and Alcatraz. The city is home to educational and cultural institutions such as the University of California, San Francisco, the University of San Francisco, San Francisco State University, the San Francisco Conservatory of Music, the Legion of Honor, the de Young Museum, the San Francisco Museum of Modern Art, the San Francisco Symphony, the San Francisco Ballet, the San Francisco Opera, the SFJAZZ Center, and the California Academy of Sciences. Two major league sports teams, the San Francisco Giants and the Golden State Warriors, play their home games within San Francisco. San Francisco International Airport (SFO) is one of the world's busiest airports, while a light rail and bus network, in tandem with the BART and Caltrain systems, connects nearly every part of San Francisco with the wider region.
San Francisco, Spanish for 'Saint Francis', takes its name from Mission San Francisco de Asís, which had been named in honor of Saint Francis of Assisi. The mission received its name in 1776, when it was founded by the Spanish under the leadership of Padre Francisco Palóu. The city has officially been known as San Francisco since 1847, when Washington Allon Bartlett, then serving as the city's alcalde, renamed it from Yerba Buena ('good herb' in Spanish), which had been the name of the first civilian pueblo in San Francisco. Earlier in San Francisco's history, the uninhabited area on the northeastern side of San Francisco was called El Paraje de Yerba Buena, after the herb that was growing abundantly there. The name "Yerba Buena" continues to be used in locations in the city, such as on Yerba Buena Island.
When using a nickname or abbreviation, local residents most commonly refer to San Francisco as "the City" or "SF". Although the nickname "Frisco" has a local pedigree dating at least to 1850 and has been used by some local residents in every generation since then, the uses of both "Frisco" and the historically more recent "San Fran" tend to elicit sharp divisions among residents.
The California Cantonese who came for the California Gold Rush called California and specifically San Francisco 金山 (Gāmsāan, "Gold Mountain"). When gold was later discovered in Melbourne, the Australian city was then called "New Gold Mountain" (Yue Chinese: 新金山, Sān Gāmsāan), while San Francisco was referred to as "Old Gold Mountain" (舊金山, Gāu Gāmsāan).
The earliest archaeological evidence of human habitation in the area dates to 3000 BCE. The Ohlone name for San Francisco was Ahwaste, meaning "place at the bay". The Yelamu group of the Ramaytush people lived in a few small villages when an overland Spanish exploration party arrived on November 2, 1769, the first documented European visit to San Francisco Bay. The arrival of Spanish colonists, and the establishment of the Mission system, marked the beginning of the assimilation of the Ramaytush people and the decline of their language and culture.
The Spanish Empire claimed San Francisco as part of Las Californias, a province of the Viceroyalty of New Spain. The Spanish first arrived in what is now San Francisco on November 2, 1769, when the Portolá expedition, led by Don Gaspar de Portolá and Juan Crespí, arrived at San Francisco Bay. Having noted the strategic benefits of the area due to its large natural harbor, the Spanish dispatched Pedro Fages in 1770 to find a more direct route to the San Francisco Peninsula from Monterey, which would become part of the El Camino Real route.
In 1774, Juan Bautista de Anza arrived in the area to select sites for a mission and presidio. The first European maritime presence in San Francisco Bay occurred on August 5, 1775, when the Spanish ship San Carlos, commanded by Juan Manuel de Ayala, became the first ship to anchor in the bay.
Soon after, on March 28, 1776, Anza established the Presidio of San Francisco and on October 9, Mission San Francisco de Asís, also known as Mission Dolores, was founded by Padre Francisco Palóu. In 1794, the Presidio established the Castillo de San Joaquín, a fortification on the southern side of the Golden Gate, which later came to be known as Fort Point.
In 1804, the province of Alta California was created, which included San Francisco. At its peak in 1810–1820, the average population at the Mission Dolores settlement was about 1,100 people.
In 1821, Spain ceded the Californias to Mexico. The extensive California mission system gradually lost its influence during the period of Mexican rule, although it was not until 1833 that the missions would be secularized. Agricultural land became largely privatized as ranchos, as was occurring in other parts of California. Coastal trade increased, including a half-dozen barques from various Atlantic ports which regularly sailed in California waters.
With the enactment of the Mexican Secularization Act of 1833, the missions were required to divest themselves of their extensive landholdings and emancipate the indigenous people under their control. As part of the process of secularization, Governor José Figueroa opened up San Francisco to civilian settlement. Prior to secularization, the only settlements in San Francisco had been the military settlement at the Presidio and the religious settlement at Mission Dolores. In 1835, the Presidio garrison, commanded by Mariano Vallejo, relocated to the Presidio of Sonoma, which was regarded as needing a greater military presence due to the proximity of the Russian settlement at Fort Ross. Only a small detachment remained at the Presidio of San Francisco. Mission Dolores sold most of its property in 1836, retaining only the church and related structures.