San Mateo County, CA demographics:
population, income, and more

Total population
742,340
-0.4% year-over-year change
Median household income
$158,855/yr
1.8% year-over-year change
Housing units
287,184
0.6% year-over-year change

San Mateo County population

How many people live in San Mateo County

San Mateo County is home to 742,340 residents, according to the most recent Census data. Gender-wise, 49.8% of San Mateo County locals are male, and 50.2% are female.

Total population
742,340
-0.4% year-over-year change
Gender ratio
Male
49.8%
369,875
Female
50.2%
372,465
Value Percent YoY change
Male 369,875 49.8% -0.4%
Female 372,465 50.2% -0.4%
A higher population often means more rental variety and livelier areas. The gender balance—how many men live here compared to women—can reveal a lot about the community and the lifestyles of its residents. Use this info to get a sense of the area's pace and personality.

Age demographics

The median age in San Mateo County is 41, with the population distributed as follows: about 16% are children under 15, then 10.9% are in the 15 to 24 age group. Adults between 25 and 44 make up 28.9% of the population, while another 26.4% fall into the 45 to 64 bracket. Finally, around 17.8% are 65 or older.

Median age
40.9
Age breakdown
Under 15
16%
15 to 24
10.9%
25 to 44
28.9%
45 to 64
26.4%
Over 65
17.8%
Value Percent YoY change
Under 15 118,896 16% -2.3%
15 to 24 80,639 10.9% 0.4%
25 to 44 214,469 28.9% -0.6%
45 to 64 196,094 26.4% -1.2%
Over 65 132,242 17.8% 2.6%
The age composition helps you get insight into who lives in the area. A younger population might mean a more active, fast-paced vibe, while an older one could suggest a quieter, slower lifestyle. If there's a balanced makeup, you’re likely to find a variety of services, housing types, and community spaces that cater to different life stages.

Racial makeup

In San Mateo County, 62.4% of the population are US-born citizens, while 22.7% have gained naturalized citizenship. At the same time, 14.9% of residents are non-citizens. As for race, 37.8% of locals are Caucasian, 2.1% are African American and 31.4% have Asian roots. Another 1.1% are Indigenous American, 1.1% are Pacific Islanders, while 11.9% identify as another race. There’s also a share of 14.4% that includes residents with two or more races.

Citizenship
U.S.-born citizens
62.4%
Non-U.S.-born citizens
22.7%
Non-citizens
14.9%
Value Percent YoY change
U.S.-born citizens 463,080 62.4% -0.7%
Non-U.S.-born citizens 168,708 22.7% -0.2%
Non-citizens 110,552 14.9% 0.8%
Racial breakdown
White
37.8%
Black or African American
2.1%
American Indian and Alaska Native
1.1%
Asian
31.4%
Native Hawaiian and other Pacific Islander
1.1%
Two or more races
14.4%
Other
11.9%
Value Percent
White 280,904 37.8%
Black or African American 15,785 2.1%
American Indian and Alaska Native 8,434 1.1%
Asian 232,971 31.4%
Native Hawaiian and other Pacific Islander 8,444 1.1%
Two or more races 107,200 14.4%
Other 88,602 11.9%

Households in San Mateo County

A peek inside San Mateo County households

San Mateo County has 264,419 households, with an average of 3 members in each. Of these, 67.9% are families, while the remaining 32.1% are made up of individuals living alone or with non-relatives, such as roommates.

Households stats

Total households
264,419
0.0% year-over-year change
Average people per household
3
Non-family households
84,928
Family households
179,491
Value Percent YoY change
Non-family households 84,928 32.1% 1.0%
Family households 179,491 67.9% -0.5%
The mix between family and non-family households gives a glimpse into daily life. A higher percentage of families might mean more parks and schools, while more non-family setups can mean flexible housing and diverse living styles. For renters, this can signal what kinds of homes are common and can help you figure out if the area matches your lifestyle.

Housing in San Mateo County

The housing landscape of San Mateo County

San Mateo County's housing consists of 287,184 units, with 55.3% being detached single-family homes ideal for those wanting space. Attached options, including duplexes and townhouses, make up 8.7% and offer a more compact, shared living style. Then there are the multifamily buildings in the area, and for those seeking flexibility, non-traditional options like mobile homes account for 1.2% of the housing landscape.

Housing units
287,184
0.6% year-over-year change
Housing types
Value Percent
1 unit, detached 158,871 55.3%
1 unit, attached 25,053 8.7%
2 units 5,690 2%
3 or 4 units 11,491 4%
5 to 9 units 16,093 5.6%
10 to 19 units 17,525 6.1%
20 to 49 units 20,625 7.2%
50 or more units 28,202 9.8%
Mobile home 3,300 1.2%
Boat, RV, van, etc. 334 0.1%
Homes built since 2020
2,945
93.8% year-over-year change

The age of buildings in San Mateo County

In San Mateo County, the median construction year is 1966. About 8.6% of homes were built before the 1940s, with another 10.3% going up by 1949. Most development happened in the second half of the 20th century. Then, 5.7% of homes were added from 2000 to 2009, 5.4% between 2010 and 2019, and 1% are part of the newest wave of development.

Construction year breakdown by decade
Value Percent YoY change
Built in 1939 or earlier 24,780 8.6% 1.9%
Built between 1940 and 1949 29,575 10.3% 0.1%
Built between 1950 and 1959 61,910 21.6% -1.4%
Built between 1960 and 1969 45,879 16% -1.6%
Built between 1970 and 1979 45,997 16% -0.2%
Built between 1980 and 1989 27,820 9.7% 1.7%
Built between 1990 and 1999 16,299 5.7% -2.7%
Built between 2000 and 2009 16,383 5.7% 3.4%
Built between 2010 and 2019 15,596 5.4% 6.1%
Built in 2020 or later 2,945 1% 93.8%
As a renter, knowing when homes were built helps you understand the potential condition and design of rental units. Newer builds may have more contemporary layouts, while older homes can offer character or larger lots, depending on the area.

San Mateo County occupancy rates

Out of the 264,419 occupied housing units in San Mateo County, 58.5% are owner-occupied, while 41.5% are lived in by tenants. Meanwhile, 7.9% of all homes on the local market sit vacant.

Occupied housing units
264,419
0.0% year-over-year change
Occupancy breakdown
Renter occupied
109,812
Owner occupied
154,607
Value Percent YoY
change
Renter occupied 109,812 41.5% 1.5%
Owner occupied 154,607 58.5% -1.1%
Unoccupied housing units
7.9%
Unoccupied housing units refer to homes that are currently without residents—whether they're waiting for renters or owners, used seasonally, or simply unclaimed. A higher share of empty homes may mean more housing availability, while a low number can reflect a tighter market with more competition. This, along with the renter-vs.-owner mix, helps paint a clearer picture of what types of housing and services are likely to be available in the area.

San Mateo County housing costs

Housing costs in San Mateo County come to a median of $3,085 per month, while tenants specifically pay a median gross rent of $2,922.

Median housing costs per month
$3,085/month
This figure sums up typical monthly housing costs for all households in the area. If you own, it includes mortgage payments in addition to property taxes, insurance and HOA fees. If you rent, it accounts for rent plus extras like utilities. It’s useful for seeing how local living expenses stack up compared to other places.
Median gross rent in San Mateo County
$2,922/month
Gross rent gives a more complete look at what renters actually pay, including not just base rent, but also utilities and fees. It’s a key number for evaluating rental affordability in your area of interest and understanding how it compares to nearby locations.

Education in San Mateo County

San Mateo County education at a glance

About 20.3% of the population in San Mateo County went to high school, while 16.4% pursued college studies. Another 6.8% earned an associate degree and 28.7% hold a bachelor’s. Meanwhile, 22.2% went even further, earning a master’s or doctorate.

Education level
Value Percent YoY change
No high school 33,783 5.7% 3.0%
High school diploma 121,055 20.3% -0.5%
College diploma 98,177 16.4% -2.3%
Associate degree 40,724 6.8% -1.0%
Bachelor's degree 171,245 28.7% 1.0%
Graduate degree 132,261 22.2% 0.7%
A community’s education mix can offer insights into the local economy and housing market. Higher levels of education often align with more job opportunities and stable incomes, which can increase demand for homes and influence both rent prices and rental availability.

Income in San Mateo County

How much people earn in San Mateo County

The average annual household income in San Mateo County was $231,822 in 2024, the most recent annual data available, according to the U.S. Census Bureau. This marked a +2.3% change from the previous year. At the same time, the median income stood at $158,855, reflecting a +1.8% shift over the same period.

Average household income in San Mateo County
$231,822/year
2.3% year-over-year change
Median household income in San Mateo County
$158,855/year
1.8% year-over-year change

San Mateo County income by age

In San Mateo County, households led by residents aged 25 to 44 — usually in the early to mid stages of their careers — have a median income of $190,774. Those with someone between 45 and 64 in charge, often well established professionally, earn $184,789 overall. Younger households, where the main provider is under 25 and just starting out, report a median income of $88,226, while those led by someone over 65, many of whom may be retired, have about $103,766 in earnings. Overall, 93.3% of the locals in this community live above the poverty line.

Income breakdown by age
Value YoY change
Under 25 $88,226 1.3%
25 - 44 $190,774 2.9%
45 - 64 $184,789 1.0%
Over 65 $103,766 3.5%
Above poverty level
679,570
Below poverty level
48,951
Value Percent YoY
change
Above poverty level 679,570 93.3% -0.6%
Below poverty level 48,951 6.7% 3.2%

Employment in San Mateo County

Workforce and job types in San Mateo County

The job market in San Mateo County is powered by 393,458 working residents, spread across a range of industries and roles. 86.6% of the working population are employed in professional or administrative positions, while 13.4% are in hands-on or service-based jobs. Also, 10.8% run their own businesses, 68.6% are employed by private companies, and 11.6% work in the public sector.

Workforce demographics

Working population
393,458
-0.4% year-over-year change
White collar
340,656
Blue collar
52,802
Value Percent YoY change
White collar 340,656 86.6% -0.3%
Blue collar 52,802 13.4% -1.2%
Employer type
Self employees
10.8%
Private companies
68.6%
Governmental workers
11.6%
Not for profit companies
9%
Value Percent YoY change
Self employees 42,344 10.8% 2.1%
Private companies 270,003 68.6% -1.0%
Governmental workers 45,720 11.6% -0.8%
Not for profit companies 35,391 9% 1.2%
Unemployment rate
4.8%
6.7% year-over-year change

Available workforce

The unemployment rate in San Mateo County stands at 4.8%, representing the share of the workforce currently without a job and actively looking for one.

For renters, the unemployment rate helps paint a picture of job security and financial stability in the area. Rates around 4% to 5% are considered typical. A lower-than-average rate might suggest strong job prospects and a thriving local economy, while a higher rate could hint at fewer opportunities—both useful to consider when planning a move.

Transportation in San Mateo County

How people get around in San Mateo County

In San Mateo County, the average commute time is 26 minutes. Commuting methods vary: 65.4% of residents travel by personal vehicle and 2.3% prefer to walk, while the remaining share relies on public transit or on two wheelers to get from A to B.

Commute time
26 min
-3.3% year-over-year change
Means of transportation
Value Percent YoY change
Car 251,447 65.4% -1.9%
Taxicab 906 0.2% -16.4%
Bus or trolleybus 8,783 2.3% -2.8%
Subway or elevated 5,723 1.5% N/A
Railroad 4,244 1.1% -27.6%
Ferryboat 13 0% -7.1%
Motorcycle 580 0.2% -29.2%
Bicycle 4,525 1.2% 0.5%
Walk 8,877 2.3% -1.9%
Understanding how locals get to work can help you plan your own routine. High car usage might mean you’ll need a vehicle, while strong public transit or walkability could save you the hassle. Commute times also play a big role in quality of life—shorter trips can give you more time for the things you enjoy.

What is the median and average household income in San Mateo County by zipcode?

Zipcode Population Number of households Median income Average income
94002 27,534 10,567 $203,965 $263,095
94005 4,692 1,912 $156,169 $264,471
94010 43,025 16,317 $196,882 $313,565
94014 45,315 14,101 $122,966 $147,620
94015 64,091 20,350 $127,056 $159,718
94019 14,419 5,221 $153,781 $214,680
94020 1,694 829 $250,001 $260,792
94021 321 128 $250,001 $276,134
94025 40,721 14,619 $216,601 $352,735
94027 7,002 2,236 $250,001 $579,268

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FAQs about San Mateo County demographics 

What is the total population of San Mateo County?

San Mateo County has a total population of 742,340 residents, according to the latest release from the U.S. Census Bureau: the 2019-2023 American Community Survey (ACS) 5-year estimates. This figure changed by -0.4% compared to a year ago.

What is the gender ratio in San Mateo County?

The gender ratio in San Mateo County is as follows:
  • 49.8% males (369,875 residents)
  • 50.2% females (372,465 residents)

What is the median age in San Mateo County?

The median age in San Mateo County is 40.9.

What is the age distribution of the population in San Mateo County?

The age distribution in San Mateo County is as follows:
  • Under 15: 16% (118,896 residents)
  • Ages 15-24: 10.9% (80,639 residents)
  • Ages 25-44: 28.9% (214,469 residents)
  • Ages 45-64: 26.4% (196,094 residents)
  • Over 65: 17.8% (132,242 residents)

What is the racial and ethnic makeup of San Mateo County?

The racial and ethnic makeup of San Mateo County is as follows:
  • White: 37.8% (280,904 residents)
  • Black or African American: 2.1% (15,785 residents)
  • American Indian and Alaska Native: 1.1% (8,434 residents)
  • Asian: 31.4% (232,971 residents)
  • Native Hawaiian and Other Pacific Islander: 1.1% (8,444 residents)
  • Two or More Races: 14.4% (107,200 residents)
  • Other: 11.9% (88,602 residents)

What percentage of the population in San Mateo County are U.S.-born citizens?

U.S.-born citizens represent 62.4% of the population in San Mateo County.

How many housing units are there in San Mateo County?

There are 287,184 housing units in San Mateo County, reflecting a +0.6% change compared to the previous year, according to the latest data from the U.S. Census Bureau.

How many households are in San Mateo County and what is the average household size?

San Mateo County has a total of 264,419 households, with an average of 3 people in each.

What is the median household income in San Mateo County?

San Mateo County has a median household income of $158,855, representing a +1.8% shift from the previous year, according to the U.S. Census Bureau.

What is the employment rate and job market overview for San Mateo County?

The employment rate is 95.2% in San Mateo County, with a workforce of 393,458 residents. Here’s a detailed breakdown of the local job market:

Job types:
  • White-collar workers: 86.6% (340,656 residents)
  • Blue-collar workers: 13.4% (52,802 residents)

Places of employment:
  • Self-employed: 10.8% (42,344 residents)
  • Private companies: 68.6% (270,003 residents)
  • Governmental workers: 11.6% (45,720 residents)
  • Not-for-profit companies: 9% (35,391 residents)

Data source & methodology

The demographic data on this page was sourced from the latest U.S. Census Bureau release—the 2019–2023 American Community Survey (ACS) 5-year estimates.

The information, issued annually, is compiled and published by the Point2Homes Research Team as soon as new data becomes available.

No representation, guarantee, or warranty is made concerning the accuracy or completeness of modified or aggregated information for particular areas.

Page last updated: September 2025