Demographics of Marin County, California

Marin County, California had 253,694 people on July 1, 2025, by the Census Bureau’s estimate: −7,643 since July 2020. Age, income, poverty, housing and origin below come from the American Community Survey, averaged over 2020–2024, each with its margin of error.

Marin County, in four figures

253,694
Population: July 1, 2025, Vintage 2025 estimate.; −2.9%
Change since July 2020: −7,643 people.; 47.4 ±0.3
Median age: ACS 2020–⁠2024.; $149,091 ±$4,474
Median household income: ACS 2020–⁠2024, in 2024 dollars.

Population, year by year

July 1 estimates from the Census Bureau’s Vintage 2025. Each year's change is births less deaths, net moves from abroad and net moves from elsewhere in the country, with the Bureau's small residual. The 2020 row's components run 3 months, from the April census to July 1.

Marin County, California's population shrank 2.9% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Marin County, California's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).

U.S. Census Bureau — Census Bureau population estimates — counties and Puerto Rico municipios, with components of change

About this chart

The figures

Marin County, California's population shrank 2.9% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Marin County, California's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).
July 1	Population	Index	United States
2020	261,337	100.0	100.0
2021	259,349	99.2	100.2
2022	257,038	98.4	100.7
2023	255,443	97.7	101.6
2024	255,704	97.8	102.5
2025	253,694	97.1	103.1

3 more columns on a wider screen

Population of Marin County, California on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	261,337	−975	−7	+3	−860
2021	259,349	−1,988	−32	+388	−2,356
2022	257,038	−2,311	+252	+1,474	−4,172
2023	255,443	−1,595	−44	+1,725	−3,319
2024	255,704	+261	+30	+1,902	−1,679
2025	253,694	−2,010	+28	+738	−2,764

Age, 2020–2024

The median age is 47.4 ±0.3: for men 45.9 ±0.2 and for women 49.0 ±0.2. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

2 more columns on a wider screen

People in Marin County by age, ACS 2020–2024
Age	People	Share	California	United States
Under 5	11,325 ±145	4.4% ±0.1	5.5% ±<0.1	5.6% ±<0.1
5 to 17	38,661 ±970	15.0% ±0.4	16.5% ±<0.1	16.3% ±<0.1
18 to 24	18,230 ±855	7.1% ±0.3	9.1% ±<0.1	9.1% ±<0.1
25 to 44	52,266 ±1,038	20.3% ±0.4	28.7% ±<0.1	26.9% ±<0.1
45 to 64	76,142 ±1,138	29.5% ±0.4	24.6% ±<0.1	24.8% ±<0.1
65 and over	61,345 ±1,499	23.8% ±0.6	15.7% ±<0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $149,091 ±$4,474, and income per person $93,920 ±$2,414, in 2024 dollars. The median is $99,122 ±$310 in California and $80,734 ±$166 in the United States.

Households by income

2 more columns on a wider screen

Households in Marin County by income, ACS 2020–2024
Household income	Households	Share	California	United States
Under $25,000	8,525 ±775	8.3% ±0.8	12.5% ±0.1	14.6% ±<0.1
$25,000 to $49,999	9,573 ±747	9.3% ±0.7	13.3% ±0.1	16.7% ±<0.1
$50,000 to $74,999	10,152 ±799	9.9% ±0.8	13.0% ±0.1	15.5% ±<0.1
$75,000 to $99,999	9,198 ±874	8.9% ±0.8	11.6% ±0.1	12.6% ±<0.1
$100,000 to $149,999	14,292 ±867	13.9% ±0.8	17.8% ±0.1	17.5% ±<0.1
$150,000 to $199,999	11,173 ±861	10.8% ±0.8	11.3% ±0.1	9.6% ±<0.1
$200,000 or more	40,105 ±1,295	38.9% ±1.2	20.5% ±0.1	13.4% ±0.1

Poverty by age

The poverty rate is the share of people whose family income is below the federal threshold for their family’s size, of everyone for whom the Bureau determines it (B17020).

2 more columns on a wider screen

Poverty rate in Marin County by age, ACS 2020–2024
Age	Below poverty	Rate	California	United States
All ages	21,068 ±1,890	8.3% ±0.7	12.0% ±0.1	12.5% ±0.1
Under 18	4,852 ±671	9.8% ±1.3	15.0% ±0.1	16.1% ±0.1
18 to 59	10,571 ±1,038	8.4% ±0.8	11.0% ±0.1	11.6% ±0.1
60 and over	5,645 ±679	7.3% ±0.9	11.5% ±0.1	11.0% ±<0.1

Housing, 2020–2024

1 more column on a wider screen

Housing in Marin County, ACS 2020–2024
Measure	Marin County	California	United States
Housing units	112,116 ±118	14,644,735 ±1,665	143,775,355 ±10,234
Occupied	91.9% ±0.6	92.5% ±0.1	89.9% ±0.1
Vacant	8.1% ±0.6	7.5% ±0.1	10.1% ±0.1
Owner occupied	64.7% ±1.0	55.9% ±0.3	65.2% ±0.3
Renter occupied	35.3% ±1.1	44.1% ±0.2	34.8% ±0.1
Median home value	$1,507,300 ±$27,346	$734,700 ±$1,307	$332,700 ±$236
Median gross rent	$2,668 ±$83	$2,036 ±$5	$1,413 ±$2
Median year built	1967 ±1	1976 ±1	1980 ±1

Occupied and vacant are shares of all housing units; owner and renter occupied are shares of occupied units. Value and rent are medians in 2024 dollars.

Origin and place of birth, 2020–2024

Hispanic or Latino origin is not a race in the Census Bureau’s tables. Here the people of Hispanic origin, of any race, are one row, and everyone else is counted by race alone (B03002), so the rows add to the whole.

Hispanic origin and race

2 more columns on a wider screen

People in Marin County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	California	United States
Hispanic or Latino	50,216 ±0	19.5% ±<0.1	40.2% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	167,816 ±1,157	65.1% ±0.4	33.8% ±<0.1	57.4% ±<0.1
Black alone, not Hispanic	5,379 ±535	2.1% ±0.2	5.2% ±<0.1	11.9% ±<0.1
Asian alone, not Hispanic	15,705 ±648	6.1% ±0.3	15.3% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	166 ±69	0.1% ±<0.1	0.3% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	435 ±193	0.2% ±0.1	0.3% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	3,117 ±866	1.2% ±0.3	0.6% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	15,135 ±1,066	5.9% ±0.4	4.4% ±<0.1	4.3% ±<0.1

Place of birth and citizenship

“Born a citizen outside the states” counts people born in Puerto Rico, the island areas, or abroad to American parents. Naturalized citizens and those who are not citizens together make up the people born abroad (B05002).

2 more columns on a wider screen

People in Marin County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	California	United States
Born in the state	131,001 ±2,093	50.8% ±0.8	56.5% ±0.1	57.3% ±<0.1
Born in another state	72,030 ±1,923	27.9% ±0.7	15.0% ±0.1	26.9% ±<0.1
Born a citizen outside the states	4,327 ±554	1.7% ±0.2	1.5% ±<0.1	1.7% ±<0.1
Born abroad	50,611 ±1,834	19.6% ±0.7	27.0% ±0.1	14.1% ±<0.1
Naturalized citizens	26,076 ±1,400	10.1% ±0.5	14.7% ±0.1	7.4% ±<0.1
Not citizens	24,535 ±1,468	9.5% ±0.6	12.3% ±0.1	6.8% ±<0.1

Marin County among the counties of California

26th of 58 by population, July 2025. Every one is listed on the California page.

Counties of California near Marin County in population, July 2025
County	July 2025	Change since 2020
Santa Barbara County	442,065	−1.4%
Monterey County	433,729	−1.5%
Merced County	297,260	+5.1%
San Luis Obispo County	282,367	< +0.1%
Santa Cruz County	258,852	−4.7%
Marin County	253,694	−2.9%
Yolo County	224,410	+3.1%
Butte County	209,211	−0.5%
El Dorado County	192,323	+0.6%
Shasta County	181,648	−0.3%
Imperial County	181,411	+1.0%

Elsewhere on the site

Sources

Census Bureau population estimates — counties and Puerto Rico municipios, with components of change — U.S. Census Bureau · U.S. Government work · retrieved September 25, 2026
American Community Survey 5-year estimates — table-based Summary File · U.S. Government work

Data retrieved September 25, 2026