San Francisco , officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California, with 815,201 residents as of 2021, and covers a land area of 46.9 square miles (121 square kilometers), at the end of the San Francisco Peninsula, making it the second most densely populated large U.S. city after New York City and the fifth most densely populated U.S. county, behind only four of the five New York City boroughs. Among the 91 U.S. cities proper with over 250,000 residents, San Francisco was ranked first by per capita income and sixth by aggregate income as of 2021. Colloquial nicknames for San Francisco include SF, San Fran, The City, Frisco, and Baghdad by the Bay.
Geography
San Francisco is located on the West Coast of the United States at the north end of the San Francisco Peninsula and includes significant stretches of the Pacific Ocean and San Francisco Bay within its boundaries. Several picturesque islands—Alcatraz, Treasure Island and the adjacent Yerba Buena Island, and small portions of Alameda Island, Red Rock Island, and Angel Island—are part of the city. Also included are the uninhabited Farallon Islands, 27 miles (43 km) offshore in the Pacific Ocean. The mainland within the city limits roughly forms a “seven-by-seven-mile square”, a common local colloquialism referring to the city’s shape, though its total area, including water, is nearly 232 square miles (600 km2).
Demographics
The 2020 United States census showed San Francisco’s population to be 873,965, an increase of 8.5% from the 2010 census. With roughly one-quarter the population density of Manhattan, San Francisco is the second-most densely populated large American city, behind only New York City among cities greater than 200,000 population, and the fifth-most densely populated U.S. county, following only four of the five New York City boroughs. San Francisco forms part of the five-county San Francisco–Oakland–Hayward, CA Metropolitan Statistical Area, a region of 4.7 million people (13th most populous in the U.S.), and has served as its traditional demographic focal point. It is also part of the greater 14-county San Jose-San Francisco-Oakland, CA Combined Statistical Area, whose population is over 9.6 million, making it the fifth-largest in the United States as of 2018.