County · California

San Mateo County, California

San Mateo County, California. San Mateo County had 743,568 residents in 2025 by the Census Bureau's estimate, down 2.7% since 2020, a steeper fall than California's (−0.5%). It holds 33 places (20 cities, villages and boroughs and 13 census-designated) and 174 census tracts. GEOID 06081.

San Mateo County is one of the 5 counties of the San Francisco-Oakland-Fremont, CA metropolitan statistical area (the Census Bureau's July 2023 delineation).

Residents, July 2025 estimate

743,568

Census Bureau estimate (no margin published)
2020 Census count: 764,442 · ACS 2020-2024: 742,340

Median household income

$158,855

±$2,851 (90% margin)
California: $99,122

Median home value

$1,559,600

±$16,159 (90% margin)
California: $734,700

Median gross rent

$2,922

±$40 (90% margin)
California: $2,036

How many people live in San Mateo County, and is it growing?

The 2020 Census counted 764,442 residents in San Mateo County. The Census Bureau estimates 743,568 for July 1, 2025, down 2.7% since 2020, a steeper fall than California's (−0.5%). The 2020-2024 American Community Survey puts the population at 742,340 over 449 square miles of land.

July 2020→2021 −23,176 (739,463)
2021→2022 −7,218 (732,245)
2022→2023 +1,704 (733,949)
2023→2024 +6,678 (740,627)
2024→2025 +2,941 (743,568)

San Mateo County in California. Boundaries: Census Bureau 2024.

Counts, ACS 2020-2024 5-year estimates, with the change from 2015-2019
Measure	San Mateo County	California	Change since 2015-2019
Total population	742,340	39,287,377	−25,083
Households	264,419±1,253	13,548,091	no clear change
Average household size	2.76±0.01	2.84	−0.11
Housing units	287,184±144	14,644,735	+9,411

San Mateo County's population since 2000

From 707,161 in 2000 to 743,568 in 2025: up 5.1%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.

2000 Census 707,161
2005 (estimate) 690,078
2010 Census 718,451
2015 (estimate) 765,479
2020 Census 764,442
2025 (estimate) 743,568

Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov

What cities and towns are in San Mateo County?

San Mateo County holds 33 places: 20 cities, villages and boroughs (incorporated places) and 13 census-designated places. The largest is San Mateo with 103,337 residents (2025 estimate). Places that cross a county line are listed with the share of their 2020 residents who live in this county.

Places in San Mateo County, ACS 2020-2024 5-year estimates. Ring: estimate with a coefficient of variation over 40%.

San Mateo	city	105,661	103,105±92	$153,504	$1,618,700	8.2%	100%
Daly City	city	104,901	101,964±54	$123,547	$1,115,000	7.7%	100%
Redwood City	city	84,292	82,447±66	$157,814	$1,801,700	6.3%	100%
South San Francisco	city	66,105	64,305±49	$136,578	$1,188,800	6.7%	100%
San Bruno	city	43,908	42,307±47	$141,272	$1,207,500	6.0%	100%
Pacifica	city	38,640	37,261±56	$160,523	$1,249,800	5.8%	100%
Foster City	city	33,805	32,792±53	$199,143	$1,838,200	4.1%	100%
Menlo Park	city	33,780	32,727±45	$210,025	$2,000,000 or more	5.8%	100%
Burlingame	city	31,386	30,525±26	$174,000	$2,000,000 or more	7.1%	100%
San Carlos	city	30,722	29,614±46	$237,470	$2,000,000 or more	3.3%	100%
East Palo Alto	city	30,034	29,069±37	$113,493	$1,102,600	10.3%	100%
Belmont	city	28,335	27,337±45	$205,297	$2,000,000 or more	6.9%	100%
Millbrae	city	23,216	22,689±27	$163,476	$1,934,900	6.0%	100%
North Fair Oaks	CDP	14,027	13,100±1,412	$104,884	$1,276,900	13.0%	100%
Half Moon Bay	city	11,795	11,391±34	$157,884	$1,549,500	5.6%	100%
Hillsborough	town	11,387	11,099±24	$250,000 or more	$2,000,000 or more	5.0%	100%
Atherton	town	7,188	6,993±21	$250,000 or more	$2,000,000 or more	5.3%	100%
El Granada	CDP	5,481	5,232±902	$213,347	$1,424,700	5.4%	100%
Woodside	town	5,309	5,126±41	$250,000 or more	$2,000,000 or more	4.5%	100%
Brisbane	city	4,851	4,692±31	$156,169	$1,232,200	5.5%	100%
Portola Valley	town	4,456	4,305±19	$250,000 or more	$2,000,000 or more	6.2%	100%
Broadmoor	CDP	4,411	4,586±1,032	$167,396	$1,254,600	2.5%	100%
Emerald Lake Hills	CDP	4,406	4,235±539	$250,000 or more	$2,000,000 or more	4.6%	100%
West Menlo Park	CDP	3,930	3,634±453	$250,000 or more	$2,000,000 or more	3.0%	100%
Moss Beach	CDP	3,214	2,683±751	$99,680	$1,123,100	9.1%	100%
Montara	CDP	2,833	2,917±807	$233,826	$1,580,700	3.4%	100%
Highlands	CDP	2,359	2,450±380	$250,000 or more	$2,000,000 or more	3.9%	100%
Baywood Park	CDP	1,693	1,580±241	$217,206	$2,000,000 or more	2.8%	100%
LaderaGEOID 0639094	CDP	1,557	1,297±360	$235,750	$2,000,000 or more	1.5%	100%
Colma	town	1,507	1,636±329	$148,295	$1,062,000	6.7%	100%
La Honda	CDP	979	1,269±437	$250,000 or more	$935,500	5.0%	100%
PescaderoGEOID 0656756	CDP	595	691±275	$250,000 or more	$1,958,300	9.1%	100%
Loma MarGEOID 0642384	CDP	134	309±275	$250,000 or more	$1,073,100	0.0%	100%

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov

Who lives in San Mateo County?

The median resident of San Mateo County is 40.9 years old; 19.5% are under 18 and 17.8% are 65 or older. The largest group is non-Hispanic white residents at 34.7%, then non-Hispanic Asian residents at 31.0%. 35.7% of residents were born outside the United States.

Age, origin and education, ACS 2020-2024 5-year estimates. Race groups are non-Hispanic; Hispanic includes any race.
Measure	San Mateo County	California	Change since 2015-2019
Median age	40.9±0.2	37.9	+1.2
Under 18 years	19.5%	22.0%	–
65 years and over	17.8%	15.7%	–
Hispanic or Latino (any race)	24.9%	40.2%	+0.5 pts
White alone, not Hispanic	34.7%±0.2 pts	33.8%	−4.5 pts
Black or African American alone, not Hispanic	2.0%±0.1 pts	5.2%	−0.2 pts
Asian alone, not Hispanic	31.0%±0.2 pts	15.3%	+2.7 pts
American Indian and Alaska Native alone, not Hispanic	0.1%±0.1 pts	0.3%	–
Native Hawaiian and Other Pacific Islander alone, not Hispanic	1.1%±0.1 pts	0.3%	–
Two or more races, not Hispanic	5.2%±0.3 pts	4.4%	–
Some other race alone, not Hispanic	0.9%±0.2 pts	0.6%	–
Born outside the United States	35.7%±0.6 pts	27.0%	+0.9 pts
Speak a language other than English at home (age 5+)	45.8%±0.6 pts	44.4%	–
Civilian veterans (age 18+)	2.9%±0.2 pts	4.3%	–
With a disability	9.4%±0.3 pts	11.6%	–
No health insurance coverage	3.8%±0.3 pts	6.6%	−0.4 pts
High school graduate or higher (age 25+)	90.2%±0.4 pts	84.7%	–
Bachelor's degree or higher (age 25+)	53.7%±0.6 pts	37.1%	+2.7 pts
Graduate or professional degree (age 25+)	24.1%±0.5 pts	14.4%	–
Moved from another state in the past year	1.5%±0.1 pts	1.1%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov

What do households in San Mateo County earn?

Half of San Mateo County's 264,419 households earn less than $158,855 a year (±$2,851), against $99,122 in California. In 2015-2019 the median was $150,934 in 2024 dollars, so it rose by $7,921 after inflation. 6.7% of residents live below the poverty line.

Income and poverty in 2024 dollars, ACS 2020-2024 5-year estimates
Measure	San Mateo County	California	Change since 2015-2019
Median household income	$158,855±$2,851	$99,122	+$7,921
Mean household income	$231,822±$3,575	$140,436	–
Per capita income	$84,288±$1,230	$49,513	+$8,545
People below the poverty line	6.7%±0.4 pts	12.0%	no clear change
Children under 18 below the poverty line	6.2%±0.8 pts	15.0%	−1.2 pts
Households receiving SNAP	5.1%±0.3 pts	12.4%	–
Households with a broadband subscription	95.7%±0.4 pts	93.5%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov

What does housing cost in San Mateo County?

Owners occupy 58.5% of San Mateo County's occupied homes and renters 41.5%. The median owner-occupied home is valued at $1,559,600 by its owner (±$16,159). The median renter pays $2,922 a month including utilities, and 40.3% of renters pay 35% or more of their income on rent.

Housing, ACS 2020-2024 5-year estimates
Measure	San Mateo County	California	Change since 2015-2019
Median home value (owner-occupied)	$1,559,600±$16,159	$734,700	+$218,882
Median gross rent	$2,922±$40	$2,036	+$72
Renters paying 35% or more of income on rent	40.3%±1.3 pts	46.0%	no clear change
Median monthly owner costs, with a mortgage	$4,000 or more	$2,946	–
Owner-occupied homes	58.5%±0.7 pts	55.9%	−1.7 pts
Housing units	287,184±144	14,644,735	+9,411
Homeowner vacancy rate	0.7%±0.2 pts	0.8%	–
Rental vacancy rate	8.5%±0.7 pts	4.2%	–
Single-family detached homes	55.3%±0.6 pts	57.0%	–
Mobile homes	1.1%±0.1 pts	3.5%	–
Built 2020 or later	1.0%±0.1 pts	1.3%	–
Built 1939 or earlier	8.6%±0.4 pts	8.9%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov

How many new homes is San Mateo County building?

Builders took permits for 2,216 new housing units across San Mateo County in 2025 (457 single-family), 3.0 per 1,000 residents.

2019 1,352 units
2020 1,074 units
2021 1,896 units
2022 1,994 units
2023 1,173 units
2024 1,088 units
2025 2,216 units

Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey

How do people in San Mateo County get to work?

56.7% of San Mateo County's workers drive alone and 24.3% work from home. The average trip to work takes 26.4 minutes. The unemployment rate in 2020-2024 averaged 4.8%.

Work and commuting, ACS 2020-2024 5-year estimates
Measure	San Mateo County	California	Change since 2015-2019
In the labor force (age 16+)	67.3%±0.4 pts	63.8%	–
Unemployment rate	4.8%±0.3 pts	6.6%	+1.1 pts
Drove alone to work	56.7%±0.7 pts	65.7%	–
Carpooled	8.7%±0.4 pts	9.5%	–
Public transportation	5.1%±0.3 pts	2.9%	–
Walked	2.3%±0.2 pts	2.4%	–
Worked from home	24.3%±0.6 pts	17.2%	+19.0 pts
Mean travel time to work	26.4 min±0.3	28.7 min	−2.9 min

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov

What are San Mateo County's census tracts?

San Mateo County is divided into 174 census tracts. Among those with a reliable estimate, median household income runs from $71,769 (Tract 6121.02) to $250,000 or more (Tract 6134).

All 174 census tracts of San Mateo County, with their figures

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov

How does San Mateo County compare with California's other counties?

San Mateo County's rank among California's counties with a reliable estimate (1 = highest)
Measure	Rank
Population	15th of 58
Growth 2020-2025	41st of 58
Residents per square mile	5th of 58
Median household income	2nd of 58
Median home value	1st of 58
Median gross rent	1st of 56
Poverty rate	56th of 57
Bachelor's degree or higher	4th of 58
Median age	21st of 58

Every county in California

Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed

How these figures are made: methodology and release checks · reading a margin of error · every state · corrections

Not on this page: crime, weather and schools for San Mateo County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.