San Marino, California demographics

San Marino, CA demographics: median age 45.7; 82.6% of adults 25+ hold a bachelor’s degree. Age, race, households, languages and education, ACS 2020–2024 with margins of error.

ACS 2020–2024 · San Marino city, California · Incorporated city · GEOID 0668224. The survey estimates a population of 12,216 for its five-year window. This is separate from the annual July 2025 population estimate on the city overview.

Median age in San Marino is 45.7 years, with a 90% margin of error of 1.8 years. There are 3,910 households (±392). Age and household distributions show how these totals are composed; they do not establish which neighborhood suits a particular person.

Every count and share is an estimate. “±” is a 90% margin of error (MOE); pp means percentage points. Derived shares use the category count divided by the named universe. Aggregated category MOEs and percentage MOEs are approximate. A margin larger than half its estimate is flagged as low precision. Blank source uncertainty is shown as unavailable, never zero.

Age distribution and sex

City, state and U.S. estimates · ACS 2020–2024
Measure / survey universe	City estimate ± MOE	State estimate ± MOE	U.S. estimate ± MOE
Median age Total population · years	45.7 ±1.8	37.9 ±0.1	38.9 ±0.1

Age groups · B01001 · ACS 2020–2024 Total population: 12,216
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Under 18	2,911 ±401	23.8% ±3.3 pp	22.0%	22.0%
18–34	1,759 ±304	14.4% ±2.5 pp	23.9%	22.8%
35–64	4,822 ±510	39.5% ±4.2 pp	38.5%	38.0%
65 and older	2,724 ±293	22.3% ±2.4 pp	15.7%	17.2%

Sex categories as published by ACS · B01001 · ACS 2020–2024 Total population: 12,216
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Male	6,181 ±286	50.6% ±2.3 pp	49.9%	49.5%
Female	6,035 ±285	49.4% ±2.3 pp	50.1%	50.5%

The age groups are mutually exclusive and cover the entire population. The sex categories follow this ACS table’s published classification; they are not a survey of gender identity.

Race and Hispanic origin

Race · B02001 · ACS 2020–2024 Total population: 12,216
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
White alone	2,770 ±454	22.7% ±3.7 pp	39.7%	61.0%
Black or African American alone	15 ±39 · low precision	0.1% ±0.3 pp · low precision	5.4%	12.2%
American Indian and Alaska Native alone	8 ±13 · low precision	0.1% ±0.1 pp · low precision	1.3%	0.9%
Asian alone	8,318 ±602	68.1% ±4.9 pp	15.5%	6.0%
Native Hawaiian and Other Pacific Islander alone	0 ±21 · low precision	0.0% ±0.2 pp · low precision	0.4%	0.2%
Some other race alone	132 ±84 · low precision	1.1% ±0.7 pp · low precision	18.5%	7.1%
Two or more races	973 ±320	8.0% ±2.6 pp	19.2%	12.6%

Hispanic or Latino origin · B03003 · ACS 2020–2024 Total population: 12,216
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Not Hispanic or Latino	11,563 ±285	94.7% ±2.3 pp	59.8%	80.7%
Hispanic or Latino	653 ±282	5.3% ±2.3 pp	40.2%	19.3%

Hispanic origin and race are separate questions. People of Hispanic or Latino origin may be of any race and appear in both tables. Do not add the Hispanic share to race shares. Race alone and two-or-more-race groups are the mutually exclusive categories of the race table.

Household types, children and living alone

Household types · B11001 · ACS 2020–2024 Households: 3,910
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Married-couple family	2,746 ±258	70.2% ±9.6 pp	48.4%	46.9%
Other family: male householder, no spouse present	133 ±67 · low precision	3.4% ±1.7 pp	6.3%	5.1%
Other family: female householder, no spouse present	464 ±123	11.9% ±2.9 pp	13.1%	12.2%
Nonfamily: householder living alone	470 ±139	12.0% ±3.3 pp	24.3%	28.7%
Nonfamily: householder not living alone	97 ±65 · low precision	2.5% ±1.6 pp · low precision	7.9%	7.0%

Households with children · B11005 · ACS 2020–2024 Households: 3,910
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Households with people under 18	1,413 ±167	36.1% ±2.3 pp	32.4%	29.5%
Households without people under 18	2,497 ±357	63.9% ±6.5 pp	67.6%	70.5%

Household size · B11016 · ACS 2020–2024 Households: 3,910
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
One-person nonfamily households	470 ±139	12.0% ±3.3 pp	24.3%	28.7%
Two-person households	1,504 ±235	38.5% ±4.6 pp	30.5%	33.8%
Three-person households	748 ±185	19.1% ±4.3 pp	16.7%	15.3%
Four-person households	803 ±174	20.5% ±4.0 pp	14.9%	12.6%
Five-person households	210 ±109 · low precision	5.4% ±2.7 pp · low precision	7.7%	5.9%
Six-person households	63 ±49 · low precision	1.6% ±1.2 pp · low precision	3.3%	2.2%
Seven or more people	112 ±98 · low precision	2.9% ±2.5 pp · low precision	2.6%	1.4%

A family household contains related people under the Census definition. A nonfamily household can contain one person or unrelated people sharing a home. Households with children can also appear in the household-type and size tables, so those tables must not be added together. Household estimates exclude people living in group quarters from the household universe.

Nativity and languages spoken at home

Nativity · B05002 · ACS 2020–2024 Total population: 12,216
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Native	6,538 ±550	53.5% ±4.5 pp	73.0%	85.9%
Foreign born	5,678 ±547	46.5% ±4.5 pp	27.0%	14.1%

Language spoken at home · C16001 · ACS 2020–2024 Population age 5 and older: 11,687
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
English only	5,062 ±499	43.3% ±4.2 pp	55.6%	77.7%
Spanish	375 ±247 · low precision	3.2% ±2.1 pp · low precision	28.3%	13.6%
French, Haitian, or Cajun	67 ±55 · low precision	0.6% ±0.5 pp · low precision	0.4%	0.7%
German or other West Germanic	57 ±46 · low precision	0.5% ±0.4 pp · low precision	0.3%	0.5%
Russian, Polish, or other Slavic	8 ±12 · low precision	0.1% ±0.1 pp · low precision	0.7%	0.7%
Other Indo-European	200 ±126 · low precision	1.7% ±1.1 pp · low precision	3.5%	2.0%
Korean	148 ±141 · low precision	1.3% ±1.2 pp · low precision	1.0%	0.3%
Chinese, including Mandarin and Cantonese	5,123 ±645	43.8% ±5.5 pp	3.5%	1.1%
Vietnamese	161 ±134 · low precision	1.4% ±1.1 pp · low precision	1.5%	0.5%
Tagalog, including Filipino	33 ±37 · low precision	0.3% ±0.3 pp · low precision	2.1%	0.6%
Other Asian and Pacific Island	416 ±177	3.6% ±1.5 pp	2.0%	1.1%
Arabic	37 ±64 · low precision	0.3% ±0.5 pp · low precision	0.6%	0.5%
Other and unspecified	0 ±21 · low precision	0.0% ±0.2 pp · low precision	0.6%	0.8%

Foreign born means not a U.S. citizen at birth; it includes naturalized citizens. Language categories describe speech at home among people age five and older. A language other than English at home does not establish that someone cannot speak English. This city page uses the published C16001 summary categories because the more detailed B16001 table does not provide these city records in this release.

Educational attainment

Highest completed education · B15003 · ACS 2020–2024 Population age 25 and older: 8,841
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Less than high school graduate	294 ±192 · low precision	3.3% ±2.2 pp · low precision	15.3%	10.4%
High school graduate or equivalency	316 ±132	3.6% ±1.5 pp	20.5%	26.0%
Some college, no degree	619 ±176	7.0% ±2.0 pp	19.3%	19.1%
Associate’s degree	306 ±135	3.5% ±1.5 pp	7.9%	8.8%
Bachelor’s degree	3,324 ±353	37.6% ±3.8 pp	22.7%	21.6%
Graduate or professional degree	3,982 ±391	45.0% ±4.2 pp	14.4%	14.1%

The denominator excludes residents under 25. Each person is counted in the highest attainment category they completed. This table does not measure the quality of local schools or the education level of every current student.

Residence one year earlier

Geographic mobility · B07003 · ACS 2020–2024 Population age 1 and older: 12,184
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Same house	10,457 ±951	85.8% ±7.8 pp	89.2%	87.7%
Moved within same county	546 ±275 · low precision	4.5% ±2.3 pp · low precision	6.4%	6.3%
Moved from a different county in the same state	212 ±187 · low precision	1.7% ±1.5 pp · low precision	2.6%	3.1%
Moved from a different state	225 ±124 · low precision	1.8% ±1.0 pp · low precision	1.1%	2.3%
Moved from abroad	744 ±997 · low precision	6.1% ±8.2 pp · low precision	0.7%	0.6%

These are respondents’ residence patterns one year before their survey response, pooled across the five-year window. They are not a net migration count for 2025. A person can move to a different house within the same city or county; moves within the same county should not automatically be interpreted as new arrivals to the city.

Health insurance, internet access and veterans

3.1% of San Marino residents (±2.0 percentage points) had no health insurance coverage when surveyed, compared with 6.6% in California and 8.4% nationally. 98.6% of households subscribe to broadband of any type, including cellular data plans. A subscription is not the same as available service: the FCC National Broadband Map shows providers at a specific address.

City, state and U.S. shares · ACS 2020–2024
Measure	San Marino	California	U.S.	Compared with California
People without health insurance Civilian noninstitutionalized population	3.1% ±2.0 pp · low precision	6.6%	8.4%	Lower
Households with a broadband subscription Households	98.6% ±13.9 pp	93.5%	91.0%	Not statistically different
Veterans Civilian population age 18 and older	1.4% ±0.7 pp	4.3%	6.2%	Lower

Reading and reusing the estimates

The Census table links above lead to the original detailed tables. Counts, source universes and uncertainty are retained in the source observation download for San Marino . Compare these figures with the same survey window; do not compare one city’s five-year estimate with another city’s annual estimate as though they measured the same period. For methods, see uncertainty and denominator calculations.

Read San Marino housing and cost context or return to the city profile.