2020 census As of the
2020 census, the county had a population of 764,442 and a median age of 39.9 years. 20.2% of residents were under the age of 18 and 16.5% were 65 years of age or older; for every 100 females there were 97.6 males, and for every 100 females age 18 and over there were 95.6 males age 18 and over. The racial makeup of the county was 39.3% White, 2.1% Black or African American, 0.9% American Indian and Alaska Native, 30.1% Asian, 1.2% Native Hawaiian and Pacific Islander, 14.1% from some other race, and 12.3% from two or more races. Hispanic or Latino residents of any race comprised 25.0% of the population. 98.3% of residents lived in urban areas, while 1.7% lived in rural areas. There were 269,417 households in the county, of which 32.9% had children under the age of 18 living with them and 24.1% had a female householder with no spouse or partner present. About 22.1% of all households were made up of individuals and 9.5% had someone living alone who was 65 years of age or older.
2010 The
2010 United States census reported that San Mateo County had a population of 718,451. The racial makeup of San Mateo County was 383,535 (53.4%)
White, 20,436 (2.8%)
African American, 3,306 (0.5%)
Native American, 178,118 (24.8%)
Asian (9.8% Filipino, 9.0% Chinese, 1.9% Indian, 1.2% Japanese, 0.8% Korean, 0.5% Vietnamese, 0.3% Burmese, 0.1% Pakistani), 10,317 (1.4%)
Pacific Islander (0.6% Tongan, 0.3% Samoan, 0.2% Fijian, 0.1% Native Hawaiian), 84,529 (11.8%) from
other races, and 38,210 (5.3%) from two or more races.
Hispanic or
Latino of any race were 182,502 persons (25.4%); 15.7% of San Mateo County is Mexican, 2.7% Salvadoran, 1.2% Guatemalan, 1.2% Nicaraguan, 0.7% Peruvian, 0.6% Puerto Rican, 0.2% Colombian, and 0.2% Cuban.
2000 As of the
census of 2009, there were 714,936 people, 258,648 households, and 174,582 families residing in the county. The
population density was . There were 284,471 housing units at an average density of . 7.4% were of
Italian, 7.1%
Irish, 7.0%
German and 5.3%
English ancestry according to
Census 2000. 46.9% spoke
English, 28.4%
Spanish, 6.2%
Tagalog, 4.0%
Chinese or
Mandarin and 1.1%
Cantonese, and other language 4.2%, as their first language from estimate census 2009. There were 258,648 households, out of which 30% had children under the age of 18, 48.6% were
married couples living together, 14.7% had a female householder with no husband present, and 41.7% were non-families. 31.5% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older. The average household size was 3.79 and the average family size was 4.44. In the county, the population was spread out, with 28.6% under the age of 18, 15.9% from 18 to 24, 25.8% from 25 to 44, 21% from 45 to 64, and 9.7% who were 65 years of age or older. The median age was 31 years. For every 100 females there were 97.8 males. For every 100 females age 18 and over, there were 95.1 males. The median income for a household in the county was $69,306, and the median income for a family was $77,737. Males had a median income of $48,342 versus $45,383 for females. The
per capita income for the county was $36,045. About 6.42% of families and 9.51% of the population were below the
poverty line, including 10.01% of those under age 18 and 8.52% of those age 65 or over. ==Government==