San Marcos, California demographics

San Marcos, CA demographics: median age 36.8; 43.8% 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 Marcos city, California · Incorporated city · GEOID 0668196. The survey estimates a population of 94,882 for its five-year window. This is separate from the annual July 2025 population estimate on the city overview.

Median age in San Marcos is 36.8 years, with a 90% margin of error of 1.1 years. There are 31,350 households (±806). 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	36.8 ±1.1	37.9 ±0.1	38.9 ±0.1

Age groups · B01001 · ACS 2020–2024 Total population: 94,882
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Under 18	23,919 ±1,531	25.2% ±1.6 pp	22.0%	22.0%
18–34	21,414 ±1,368	22.6% ±1.4 pp	23.9%	22.8%
35–64	37,043 ±1,521	39.0% ±1.6 pp	38.5%	38.0%
65 and older	12,506 ±893	13.2% ±0.9 pp	15.7%	17.2%

Sex categories as published by ACS · B01001 · ACS 2020–2024 Total population: 94,882
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Male	46,386 ±1,192	48.9% ±1.3 pp	49.9%	49.5%
Female	48,496 ±1,197	51.1% ±1.3 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: 94,882
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
White alone	48,024 ±2,313	50.6% ±2.4 pp	39.7%	61.0%
Black or African American alone	1,265 ±309	1.3% ±0.3 pp	5.4%	12.2%
American Indian and Alaska Native alone	1,021 ±380	1.1% ±0.4 pp	1.3%	0.9%
Asian alone	11,157 ±1,116	11.8% ±1.2 pp	15.5%	6.0%
Native Hawaiian and Other Pacific Islander alone	180 ±135 · low precision	0.2% ±0.1 pp · low precision	0.4%	0.2%
Some other race alone	12,925 ±1,508	13.6% ±1.6 pp	18.5%	7.1%
Two or more races	20,310 ±1,730	21.4% ±1.8 pp	19.2%	12.6%

Hispanic or Latino origin · B03003 · ACS 2020–2024 Total population: 94,882
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Not Hispanic or Latino	60,009 ±1,925	63.2% ±2.0 pp	59.8%	80.7%
Hispanic or Latino	34,873 ±1,931	36.8% ±2.0 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: 31,350
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Married-couple family	18,170 ±731	58.0% ±1.8 pp	48.4%	46.9%
Other family: male householder, no spouse present	1,385 ±333	4.4% ±1.1 pp	6.3%	5.1%
Other family: female householder, no spouse present	3,845 ±477	12.3% ±1.5 pp	13.1%	12.2%
Nonfamily: householder living alone	6,023 ±629	19.2% ±1.9 pp	24.3%	28.7%
Nonfamily: householder not living alone	1,927 ±335	6.1% ±1.1 pp	7.9%	7.0%

Households with children · B11005 · ACS 2020–2024 Households: 31,350
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Households with people under 18	12,574 ±566	40.1% ±1.5 pp	32.4%	29.5%
Households without people under 18	18,776 ±1,014	59.9% ±2.8 pp	67.6%	70.5%

Household size · B11016 · ACS 2020–2024 Households: 31,350
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
One-person nonfamily households	6,023 ±629	19.2% ±1.9 pp	24.3%	28.7%
Two-person households	9,273 ±829	29.6% ±2.5 pp	30.5%	33.8%
Three-person households	5,829 ±572	18.6% ±1.8 pp	16.7%	15.3%
Four-person households	5,877 ±593	18.7% ±1.8 pp	14.9%	12.6%
Five-person households	2,926 ±344	9.3% ±1.1 pp	7.7%	5.9%
Six-person households	944 ±329	3.0% ±1.0 pp	3.3%	2.2%
Seven or more people	478 ±153	1.5% ±0.5 pp	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: 94,882
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Native	73,748 ±1,593	77.7% ±1.7 pp	73.0%	85.9%
Foreign born	21,134 ±1,587	22.3% ±1.7 pp	27.0%	14.1%

Language spoken at home · C16001 · ACS 2020–2024 Population age 5 and older: 89,081
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
English only	57,711 ±2,040	64.8% ±2.2 pp	55.6%	77.7%
Spanish	22,136 ±1,907	24.8% ±2.1 pp	28.3%	13.6%
French, Haitian, or Cajun	202 ±185 · low precision	0.2% ±0.2 pp · low precision	0.4%	0.7%
German or other West Germanic	164 ±107 · low precision	0.2% ±0.1 pp · low precision	0.3%	0.5%
Russian, Polish, or other Slavic	945 ±392	1.1% ±0.4 pp	0.7%	0.7%
Other Indo-European	1,950 ±438	2.2% ±0.5 pp	3.5%	2.0%
Korean	298 ±154 · low precision	0.3% ±0.2 pp · low precision	1.0%	0.3%
Chinese, including Mandarin and Cantonese	1,137 ±431	1.3% ±0.5 pp	3.5%	1.1%
Vietnamese	1,139 ±330	1.3% ±0.4 pp	1.5%	0.5%
Tagalog, including Filipino	1,530 ±369	1.7% ±0.4 pp	2.1%	0.6%
Other Asian and Pacific Island	1,405 ±803 · low precision	1.6% ±0.9 pp · low precision	2.0%	1.1%
Arabic	351 ±173	0.4% ±0.2 pp	0.6%	0.5%
Other and unspecified	113 ±73 · low precision	0.1% ±0.1 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: 61,920
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Less than high school graduate	7,295 ±748	11.8% ±1.2 pp	15.3%	10.4%
High school graduate or equivalency	10,155 ±765	16.4% ±1.2 pp	20.5%	26.0%
Some college, no degree	12,036 ±935	19.4% ±1.5 pp	19.3%	19.1%
Associate’s degree	5,307 ±716	8.6% ±1.1 pp	7.9%	8.8%
Bachelor’s degree	17,522 ±1,123	28.3% ±1.7 pp	22.7%	21.6%
Graduate or professional degree	9,605 ±764	15.5% ±1.2 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: 94,097
Category	Count ± MOE	Share ± MOE (pp)	California	U.S.
Same house	82,595 ±1,897	87.8% ±2.0 pp	89.2%	87.7%
Moved within same county	8,345 ±1,772	8.9% ±1.9 pp	6.4%	6.3%
Moved from a different county in the same state	1,602 ±523	1.7% ±0.6 pp	2.6%	3.1%
Moved from a different state	1,213 ±275	1.3% ±0.3 pp	1.1%	2.3%
Moved from abroad	342 ±194 · low precision	0.4% ±0.2 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

7.1% of San Marcos residents (±0.8 percentage points) had no health insurance coverage when surveyed, compared with 6.6% in California and 8.4% nationally. 95.9% 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 Marcos	California	U.S.	Compared with California
People without health insurance Civilian noninstitutionalized population	7.1% ±0.8 pp	6.6%	8.4%	Not statistically different
Households with a broadband subscription Households	95.9% ±0.7 pp	93.5%	91.0%	Higher
Veterans Civilian population age 18 and older	5.8% ±0.8 pp	4.3%	6.2%	Higher

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 Marcos . 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 Marcos housing and cost context or return to the city profile.