Population
743,568
2025
−2.5% since 2020
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. Resident population, July 1 estimate.
San Mateo County, CA: population growth, jobs and income
San Mateo County gained 2,941 residents between 2024 and 2025 (+0.4%).
San Mateo County had an estimated 743,568 residents in 2025, down 2.5% (19,071 fewer people) since 2020. That is slower than California as a whole (−0.4%), and the 39th fastest growth of 58 counties in California.
Data as of 2025 · updated
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In the San Mateo County report
One-time $99 PDF: everything on this page for San Mateo County, ranked against California and the U.S., plus these figures that are not on the free page:
- Median gross rent$2,922/mo2020–24
- Vacant homes, incl. seasonal and second homes7.9%2020–24
- New homes permitted, last 12 months1,7532025-10/2026-09
- Rent growth, 5 yearsIn the report
- Permits in 5+ unit buildingsIn the report
- IRS income moving in (net AGI)In the report
- Neighbouring-county comparison tableIn the report
What's inside: 5 pages
- 1 Summary, headline numbers and ranks (free preview)
- 2 Ranks and the neighbouring-county table
- 3 Migration, with IRS mover and income flows
- 4 Rent, vacant homes, permits and employers
- 5 Every source and the methods
Headline numbers
Net domestic migration
−4,110
2025
−5.5 per 1,000 residents
−64,201 in total, 2021–2025
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. People moving in from other U.S. counties minus people moving out.
Unemployment rate
3.9%
2025
+1.7 pts since 2019
Source: U.S. Bureau of Labor Statistics, Local Area Unemployment Statistics, 2025. Annual average unemployment rate.
New homes permitted
2,216
2025
+16.9% since 2021
3.0 per 1,000 residents
Source: U.S. Census Bureau, Building Permits Survey, 2025. Housing units authorized by building permits in the year.
Median household income
$158,855
2020–24
+24.0% since 2016–20
Source: U.S. Census Bureau, American Community Survey 5-year estimates, 2020–24. American Community Survey 5-year estimate.
Private-sector employment
477,938
2023
+19.8% since 2018
Source: U.S. Census Bureau, County Business Patterns, 2023. Paid employees of private employers in mid-March (County Business Patterns).
What the numbers say
Net domestic migration was negative in 2025: 4,110 more people moved out to other U.S. counties than moved in.
Private employers had 477,938 paid employees in mid-March 2023, +19.8% since 2018 (County Business Patterns).
Unemployment averaged 3.9% in 2025, 1.7 points higher than in 2019 (before the pandemic).
Builders were authorized to start 2,216 new homes in 2025, or 3.0 per 1,000 residents.
Median household income was $158,855 in the 2020–24 American Community Survey, +24.0% since 2016–20.
Across the 3,107 U.S. counties with a comparable estimate, its population growth ranks 2,580th.
Part of the San Francisco-Oakland-Fremont, CA metro area.
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San Mateo County population by year
| Year | Population | Change |
|---|---|---|
| 2025 | 743,568 | +2,941 |
| 2024 | 740,627 | +6,678 |
| 2023 | 733,949 | +1,704 |
| 2022 | 732,245 | −7,218 |
| 2021 | 739,463 | −23,176 |
| 2020 | 762,639 | – |
Census Bureau population estimates, July 1 of each year.
What drove the change in San Mateo County
San Mateo County lost 19,071 people since 2020; the biggest drag was domestic migration (−64,201).
| Component | 2025 | 2020–25 | Share |
|---|---|---|---|
| Natural changebirths minus deaths | +2,279 | +11,574 | |
| International migrationfrom and to other countries | +4,737 | +34,506 | |
| Domestic migrationfrom and to other U.S. counties | −4,110 | −64,201 | |
| Census adjustmentbalancing residual | +35 | −950 | |
| Total change | +2,941 | −19,071 |
Census Bureau population estimates, components of change, each year July 1 to June 30. The components add up to the change in the estimate; the Census adjustment is the small balancing figure the Bureau publishes.
How it ranks
| Measure | In California | Among U.S. counties |
|---|---|---|
| Population growth | 39th of 58 | 2,580th of 3,107 |
| Net domestic migration per 1,000 residents | 35th of 58 | 2,608th of 3,108 |
| Private-sector job growth | 2nd of 58 | 222nd of 3,092 |
| Median household income | 2nd of 58 | 3rd of 3,107 |
| Lowest unemployment rate | 1st of 58 | 1,379th of 3,108 |
| New homes permitted per 1,000 residents | 20th of 58 | 1,126th of 3,005 |
1st = highest (lowest for unemployment). Counties are ranked only against others with a figure for the same period.
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The County Growth and Demographics Report for San Mateo County, CA as a PDF, from federal data: population and migration, housing and rents, permits, private employers and jobs, unemployment, ranks in the state and the country, and neighbouring counties, with a source next to every number. Pay once, no subscription.
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Neighbouring counties
Over 2020–25, San Mateo County's population change (−2.5%) was ahead of 3 of its 4 neighbouring counties and behind 1 (Santa Clara County).
Only Santa Clara County had a higher median household income (2020–24) among its 4 neighbouring counties; San Mateo County's was $158,855.
| County | Population2025 | Population change2020–25 | Net domestic migration per 1,000 residents2025 | Homes permitted per 1,000 residents2025 | Median household income2020–24 |
|---|---|---|---|---|---|
| San Mateo County, CA This county | 743,568 | −2.5% | −5.5 | 3.0 | $158,855 |
| San Francisco County, CA | 826,079 | −5.6% | −0.2 | 1.7 | $140,970 |
| Santa Cruz County, CA | 258,852 | −4.7% | −10.4 | 1.8 | $111,093 |
| Alameda County, CA | 1,636,630 | −2.6% | −9.8 | 1.7 | $129,367 |
| Santa Clara County, CA | 1,914,391 | −0.9% | −10.3 | 2.8 | $164,281 |
Census Bureau population estimates and building permits, American Community Survey 5-year income. Rates per 1,000 residents. – means no figure, or a base too small for a change or rate (it would swing on a few people). A figure from another period shows its year and is left out of the comparison.
Questions
Is San Mateo County growing?
No. Its population fell 2.5% between 2020 and 2025, about 19,071 fewer people (Census Bureau population estimates). California as a whole changed −0.4% over the same years. That ranks 39th of 58 counties in California for population growth.
How many people moved to San Mateo County?
On net, none in 2025: about 4,110 more people moved out to other U.S. counties than moved in (Census Bureau net domestic migration estimate).
What is the unemployment rate in San Mateo County?
It averaged 3.9% in 2025 (BLS Local Area Unemployment Statistics, annual average).
What is the population of San Mateo County?
About 743,568 people, according to the U.S. Census Bureau's population estimate for July 1, 2025.
How many jobs are in San Mateo County?
Private employers there had 477,938 paid employees in mid-March 2023, +19.8% since 2018 (Census Bureau County Business Patterns; government jobs and the self-employed are not counted).
What Beacon CRE covers in California
Map, parcel and listing layers cover North and South Carolina only for now. This page and the other California county pages carry the public federal growth figures.
San Mateo County data alerts
Email me when San Mateo County gets new Census numbers: population, building permits, jobs and income. About 4 emails a year, one click to stop.
Sources and method
- U.S. Census Bureau, Population Estimates Program (Vintage 2025)
- U.S. Bureau of Labor Statistics, Local Area Unemployment Statistics
- U.S. Census Bureau, Building Permits Survey
- U.S. Census Bureau, American Community Survey 5-year estimates
- U.S. Census Bureau, County Business Patterns
Each number shows its own period. Changes compare the latest period with five years earlier (or the earliest period available). Beacon CRE last refreshed these figures on 2026-11-05. Figures come from public federal statistics and are informational only, not investment advice. Check the source before relying on a number. Methodology: how we compute every number. More on every layer: data sources and licences.
Jobs outside North and South Carolina use County Business Patterns (paid private-sector employees in mid-March); wages and government jobs are not included.