Marin County, California Population 2026

Updated April 2026 · US Census ACS 2023 5-Year Estimates · 26th-largest in California

The population of Marin County, California is 258,765 as of the 2023 American Community Survey, making it the 26th-largest county in California. The median household income is $142,785, the median home value is $1,390,000, and the median age is 47.3.

The population of Marin County has grown 1.4% since 2010 (252,906 → 256,400), a +0.10% annualized rate.

Marin County within California · Source: US Census TIGER/Line via us-atlas

258,765

Population

+0.10%

Annual growth

497

People / sq mi

$142,785

Median Income

$1,390,000

Median Home Value

Marin County covers 520 sq mi of land at 497.5 people per square mile.

About Marin County, CA

Marin County is a county in California with a population of 258,765. It ranks #26 among counties in California by population. The median age is 47.3, older than the national median. The population is 49.1% male and 50.9% female.

The median household income in Marin County is $142,785, above the US median of $74,580. 4.0% of residents live below the federal poverty level. Home values sit at a median of $1,390,000, with monthly rent averaging $2,584. The homeownership rate of 63.9% is close to the national rate of 64.8%.

Educational attainment in Marin County reflects 60.5% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 27.9% of workers primarily work from home, noticeably above the national work-from-home rate of 14.2%. The average commute is 28.3 minutes each way.

Marin County Population History (2010-2024)

The county of Marin County had a population of 252,906 in 2010 and 256,400 in 2024, a 1.4% growth over 14 years. The peak was 261,341 in 2020. Average annual growth rate: 0.10%.

256,400

Population (2024)

252,906

Population (2010)

261,341

Peak (2020)

0.10%

Avg Annual Growth

Year	Population	Change	Annual %	Source
2010	252,906	-	-	estimate
2011	255,380	+2,474	+0.98%	estimate
2012	256,087	+707	+0.28%	estimate
2013	258,441	+2,354	+0.92%	estimate
2014	260,403	+1,962	+0.76%	estimate
2015	260,974	+571	+0.22%	estimate
2016	260,722	-252	-0.10%	estimate
2017	259,975	-747	-0.29%	estimate
2018	260,091	+116	+0.04%	estimate
2019	259,085	-1,006	-0.39%	estimate
2020	261,341	+2,256	+0.87%	estimate
2021	259,254	-2,087	-0.80%	estimate
2022	257,143	-2,111	-0.81%	estimate
2023	255,706	-1,437	-0.56%	estimate
2024	256,400	+694	+0.27%	estimate

Race & Ethnicity

White	70.4%
Black or African American	2.3%
Asian	0.0%
Hispanic or Latino (any race)	1.9%
Two or More Races	0.0%

Age & Sex

47.3

Median Age

50.9%

Female

49.1%

Male

23.2%

Age 65+

Age Distribution

Under 5

4.4%

5–9

5.3%

10–14

5.9%

15–19

6.2%

20–24

4.7%

25–34

8.5%

35–44

11.8%

45–54

14.9%

55–59

8.1%

60–64

6.9%

65–74

13.1%

75–84

7.3%

85+

2.8%

Children (under 15): 15.6% · Seniors (65+): 23.2%

Income & Poverty

Median household income	$142,785+$46,451 vs state
Mean household income	$224,140
Per-capita income	$90,408
Poverty rate	4.0%-4.4% vs state
Unemployment rate	3.8%
Employment-to-population	58.8%

Top Industries by Employment

Finance & real estate

21.9%

Professional & business services

20.8%

Information

8.8%

Education & health care

8.3%

Construction

6.4%

Arts, entertainment & food

5.4%

Manufacturing

4.9%

Transportation & utilities

4.3%

The largest employment sector in Marin County is finance & real estate, accounting for 21.9% of workers.

How residents commute

4.9%

Drive alone

3.5%

Carpool

53.7%

Public transit

27.9%

Work from home

28.3 min

Avg commute

Housing

$1,390,000+$694,600 vs state

Median home value

$2,584

Median rent

63.9%

Homeownership rate

111,860

Total housing units

92.3%

Occupied

7.7%

Vacant

36.1%

Renter-occupied

Social & access

96.2%

With health insurance

97.5%

With broadband internet

28.0%

Foreign-born

3.8%

Veterans (18+)

9.7%

With a disability

76.9%

Speak language other than English at home

Education

92.7%

High School+

60.5%

Bachelor's+

Largest cities in California

Los Angeles (3,857,897)San Diego (1,385,061)San Jose (990,054)San Francisco (836,321)Fresno (543,615)Sacramento (524,802)Long Beach (458,491)Oakland (438,072)Bakersfield (408,366)Anaheim (344,553)All California cities →

Other counties in California

Los Angeles County (9,848,406)San Diego County (3,282,782)Orange County (3,164,063)Riverside County (2,449,909)San Bernardino County (2,187,816)Santa Clara County (1,903,297)Alameda County (1,651,949)Sacramento County (1,584,047)Contra Costa County (1,161,458)Fresno County (1,012,152)All California counties →

Part of California

California demographic profile All California data →

Metro areas in California

Los Angeles (13,012,469)San Francisco (4,653,593)Riverside (4,637,725)San Diego (3,282,782)Sacramento (2,406,563)San Jose (1,969,353)Fresno (1,170,942)Bakersfield (910,433)All US metros →

County rankings

US Counties by Population Richest US Counties by Median Household Income Expensive US Counties by Home Value Educated US Counties Counties With Highest Poverty Rates Youngest US Counties by Median Age Oldest US Counties by Median Age Cheapest US Counties by Median Home Value Racially Diverse US Counties Counties With Largest Hispanic Population All rankings →

Frequently Asked Questions

Marin County, California has a population of 258,765 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 26th-largest county in California. Population density is 497 people per square mile.

The population of Marin County has grown 1.4% since 2010 (252,906 → 256,400), a +0.10% annualized rate.

The median household income in Marin County, California is $142,785, with mean (average) household income of $224,140 and per-capita income of $90,408. 4.0% of residents live below the federal poverty level.

In Marin County, the largest racial and ethnic groups are White (70.4%), Black or African American (2.3%), Hispanic or Latino (1.9%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.

The median age in Marin County, California is 47.3 years. Residents are 50.9% female and 49.1% male.

The median home value in Marin County is $1,390,000 and median monthly rent is $2,584. 63.9% of occupied housing units are owner-occupied. The county has 111,860 total housing units, 7.7% of which are vacant.

The largest employment sector in Marin County, California is finance, insurance, and real estate, employing 21.9% of workers. The unemployment rate is 3.8%.

Los Angeles is among the largest cities associated with Marin County, California, with a population of 3,857,897.