South San Francisco is a city in San Mateo County, California, United States, on the San Francisco Peninsula in the San Francisco Bay Area. The city is colloquially termed "South City". The population was 66,105 as of the 2020 census, and was estimated at 64,941 in 2025.
History Parts of what is now South San Francisco have been populated for more than 5,000 years. The northern San Francisco Peninsula was inhabited by the Ramaytush, a linguistic sub-group of Ohlone people. Their village of Urebure on San Bruno Creek was visited by the Gaspar de Portolà expedition in 1769; remains of long-term (5,000+ years) inhabitancy and seasonal encampments have been examined at the Siplichiquin and Buckeye shell-mounds on San Bruno Mountain. Charcoal-sampling indicates these ancient sites were actively occupied into the Spanish colonial period (late 1700s). The delta of Colma Creek was formerly an important habitat for the waterfowl known to be hunted by the Ramaytush in historic times, and archaeologic sites have been recorded near the creek. The city's plan recognizes the existing remains of a village (CA-SMA-299) along El Camino Real.
In 1835, the area which is now South San Francisco was confirmed to be part of Rancho Buri Buri, a large Mexican land grant to the Sanchez family, which they had used for cattle-ranching (with an easement for southbound traffic) for nearly a decade. While the Treaty of Guadalupe Hidalgo guaranteed the grant, taxes and legal-fees encouraged family-members to sell parts of the grant. Around that same time, the 12-Mile House was built as a stop on the San Jose Stage road. In 1853 SF butcher Charles Lux and business partner Alfred Edmondson, purchased in Rancho Buri Buri. In 1855 Lux bought another of Buri Buri land and soon partnered with fellow San Francisco butcher and entrepreneur Henry Miller, forming the stockyards and beef-raising firm of Miller & Lux. Lux bought out Edmonson's interest in 1856 and founded the town of Baden (now a neighborhood of South San Francisco) near the 12-Mile House. In 1863, Baden became a station as the San Francisco and San Jose Railroad was built.
The city of South San Francisco was conceived as an industrial suburb and was promoted by representatives of the Beef Trust, a group including some of the country's largest meat packing firms. A city plan was put forward in 1888 by Gustavus Franklin Swift, founder of the Swift & Company meat packing firm. The plan called for multiple individual meat-packing companies with a shared stockyard, as well as a residential area for employees. Swift proposed the name South San Francisco based on South Chicago and South Omaha, where the Swift company already had plants.
In 1890 Peter E. Iler of Omaha, Nebraska, an agent of the Beef Trust, purchased the Lux properties; ownership was transferred to the South San Francisco Land and Improvement Company in 1891. It was divided into industrial and residential districts, and the company installed lighting, sewer connections, and water distributions in the residential areas. A second corporation, eventually known as the Western Meat Company, set up stock yards and meat packing facilities on of bayfront property; the facility opened in 1892. Other industries soon moved in, including a pottery works, two brick companies, the paint manufacturer W.P. Fuller & Company, the South San Francisco Lumber Company, and the Pacific Jupiter Steel Company.
The city of South San Francisco was incorporated in 1908 following a dispute with San Mateo County, which had blocked the construction of a smelter on San Bruno Point supported by the locals. Following incorporation additional industries moved into the town, including two steel mills. A new City Hall was opened on November 11, 1920.
By the 1920s the city was "the smokestack capital of the Peninsula." South San Francisco proudly called itself "The Industrial City", a motto immortalized in 1923 by a huge sign on a hillside overlooking the city. Industry remained the city's main economic focus through the 1950s. During the Great Depression the city maintained 35 industrial operations, including four meat-packing businesses, six iron or steel plants, a smelter for precious metals, seven equipment manufacturers of various kinds, two large paint factories, three other chemical works, and three food packing establishments. During World War II shipbuilding also became a significant operation. From August 1940, until the end of the War, a total of 48 ships were built and launched at the Western Pipe & Steel Shipyards.
At the end of the war the city's focus shifted away from "smokestack industries" toward light industry, warehousing, and residential development. The major manufacturers closed, and new development was focused on office parks, housing, high-rise hotels, and yacht harbors. The biotechnology giant Genentech opened in 1976, leading to South San Francisco's new identity as "the birthplace of biotechnology".
Geography According to the United States Census Bureau, the city has an area of , of which is land and (69.50%) is water.
South San Francisco lies north of San Bruno and San Francisco International Airport in the Colma Creek valley south of Daly City, Colma, Brisbane, and San Bruno Mountain; east of Pacifica and the hills of the northern Coast Range lying along the San Andreas Fault; west of the waters of San Francisco Bay. Locals often refer to the town as South City, in much the same way that San Francisco is called "The City." South San Francisco does not touch on San Francisco, with either Brisbane, Colma, or Daly City lying between them.
Two San Mateo County unincorporated areas lie within the boundaries of the city: the largest is owned by the city and is mostly leased to the private California Golf Club (an adjacent portion is occupied by Ponderosa Elementary School, controlled by the South San Francisco Unified School District. The other is Country Club Park - located along Country Club Drive and Alta Vista Drive between the Avalon and Brentwood neighborhoods. The city provides some services to these areas.
The city is particularly noted for the South San Francisco hillside sign on Sign Hill, which rises to the north of the city, with large white letters that proclaim, "South San Francisco, The Industrial City". The sign, a tribute to the city's industrial past, is listed on the National Register of Historic Places.
Climate South San Francisco, along with most of the Bay Area, has a mild mediterranean climate (Köppen climate classification Csb), with warm, dry summers and cool, relatively wet winters. Much of the valley faces east toward San Francisco Bay, affording bay views from higher levels. South San Francisco has mild winters and dry cool summers. The hills to the west shield the eastern parts of the city from some of the fog that prevails in neighboring areas.
The microclimate of South San Francisco is dominated by wind from the nearby Pacific Ocean, which typically keeps the daytime temperatures quite cool year round, even during the summer months. January is the coolest month with August being the warmest month. The record highest temperature of and was recorded on June 14, 1961. The record lowest temperature of was recorded on December 9, 1972. Normal annual precipitation is .
South San Francisco is frequently windy. Summer is the windiest season, with winds averaging ; winter is the least windy season, with winds averaging .http://wind-speed.weatherdb.com/l/43/South-San-Francisco-California
Month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annual Wind (mph) 7.2 8.6 10.5 12.2 13.4 14.0 13.6 12.8 11.1 9.4 7.5 7.1 10.6
Demographics
The population grew from less than 2,000 in 1910 to more than 65,000 in 2024. It more than tripled in the thirty years following World War II with the opening of such subdivisions as Buri Buri, Winston Manor and Westborough on the slopes west of El Camino. The city has grown about 30% since 1985 as smaller fallow and commercial properties were developed, and single-family homes in the downtown area were replaced by denser housing.
According to realtor website Zillow, the average price of a home as of July 31, 2026, in South San Francisco was $1,235,804.
As of the 2024 American Community Survey, there were 21,838 estimated households in South San Francisco with an average of 2.90 persons per household. The city has a median household income of $136,578. Approximately 6.7% of the city's population lives at or below the poverty line. South San Francisco has an estimated 65.1% employment rate, with 40.8% of the population holding a bachelor's degree or higher and 86.0% holding a high school diploma. There were 21,650 housing units at an average density of .
The top five reported languages (people were allowed to report up to two languages, thus the figures will generally add to more than 100%) were English (46.2%), Spanish (20.7%), Indo-European (4.3%), Asian and Pacific Islander (26.6%), and Other (2.2%).
The median age in the city was 43.2 years.
+South San Francisco, California – racial and ethnic composition Race / ethnicity (NH = non-Hispanic) Pop. 1980 Pop. 1990 Pop. 2000 Pop. 2010 White alone (NH) 29,716(60.16%) 24,258(44.66%) 18,487(30.53%) 14,016(22.03%) 11,905(18.01%) Black or African American alone (NH) 1,775(3.59%) 2,054(3.78%) 1,621(2.68%) 1,480(2.33%) 1,184(1.79%) Native American or Alaska Native alone (NH) 138(0.28%) 285(0.52%) 197(0.33%) 138(0.22%) 125(0.19%) Asian alone (NH) 6,654(13.47%) 12,862(23.68%) 17,312(28.59%) 22,923(36.02%) 26,994(40.84%) Pacific Islander alone (NH) — — 896(1.48%) 1,054(1.66%) 996(1.51%) Other race alone (NH) 161(0.33%) 122(0.22%) 264(0.44%) 287(0.45%) 508(0.77%) Mixed race or multiracial (NH) — — 2,493(4.12%) 2,089(3.28%) 2,743(4.15%) Hispanic or Latino (any race) 10,949(22.17%) 14,731(27.12%) 19,282(31.84%) 21,645(34.02%) 21,650(32.75%) Total 49,393(100.00%) 54,312(100.00%) 60,552(100.00%) 63,632(100.00%) 66,105(100.00%)
2020 census As of the 2020 census, there were 66,105 people, 21,803 households, and 15,803 families residing in the city. The population density was . There were 22,683 housing units at an average density of . The racial makeup of the city was 22.06% White, 1.98% African American, 1.11% Native American, 41.40% Asian, 1.60% Pacific Islander, 18.48% from some other races and 13.37% from two or more races. Hispanic or Latino people of any race were 32.75% of the population.
2010 census As of the 2010 census, there were 63,632 people, 20,938 households, and 15,330 families residing in the city. The population density was . There were 21,814 housing units at an average density of . The racial makeup of the city was 37.34% White, 2.55% African American, 0.62% Native American, 36.61% Asian, 1.75% Pacific Islander, 15.08% from some other races and 6.05% from two or more races. Hispanic or Latino people of any race were 34.02% of the population.
There were 20,938 households out of which 36.2% had children under the age of 18 living with them, 53.3% were married couples living together, 13.8% had a female householder with no husband present, and 5.2% were non-families. 20.5% of all households were made up of individuals and 8.9% had someone living alone who was 65 years of age or older. The average household size was 3.01 and the average family size was 3.45.
In the city the population was spread out with 21.7% under the age of 18, 8.9% from 18 to 24, 29.3% from 25 to 44, 27.0% from 45 to 64, and 13.1% who were 65 years of age or older. The median age was 38.1 years. For every 100 females there were 97.6 males. For every 100 females age 18 and over, there were 95.7 males.
2000 census