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San Marcos city, TX

ZIP 78666 — People & Community

Source: U.S. Census Bureau ACS 2019–2023 5-Year Estimates. Page data updated 2026-08-02.

Working ClassLarge CommunityLow Snow Area

Demographics, education attainment, health access, and community lifestyle

Population & Demographics in 78666

78666 has a population of 87,775 with a median age of 27.0 yrs (48.2% male).

Race & Ethnicity
White
63.7%+3% vs US avg
x
Black
5.2%-58% vs US avg
x
Asian
1.8%-70% vs US avg
x
Hispanic
43.8%+134% vs US avg
x
Age Groups
0–17
13.8%-38% vs US avg
x
18–64
73.8%+20% vs US avg
x
65+
12.5%-24% vs US avg
x
Education
Less than HS
10.7%-4% vs US avg
x
High school
23.9%-9% vs US avg
x
Some college
30.7%+6% vs US avg
x
Bachelor's+
34.6%+3% vs US avg
x
Marital Status
Married
33.7%-30% vs US avg
x
Never married
54.2%+60% vs US avg
x
Divorced
8.5%-17% vs US avg
x
Widowed / Separated
3.5%
x
Diversity Index
40/100

Higher = more diverse (Simpson index from race/ethnicity)

Social & household profile

Poverty, nativity, veterans, disability, family structure, and births (ACS).

Poverty Rate
23.3%+103% vs US avg
x
Foreign Born
34.0%+144% vs US avg
x
Veterans
4.8%-21% vs US avg
x
Disability
15.2%+13% vs US avg
x
Single Parent
9.6%+19% vs US avg
x
Recent Births
25.7%+344% vs US avg
x
Top ancestry
GermanEnglishIrish

Health & Community Indicators in 78666

Poverty Rate
23.3%+103% vs US avg
x
Veterans
4.8%-21% vs US avg
x
Foreign Born
34.0%+144% vs US avg
x
Single Parent
9.6%+19% vs US avg
x
Disability
15.2%+13% vs US avg
x
Uninsured
16.1%+102% vs US avg
x
SNAP Benefits
8.1%-31% vs US avg
x
Private School
0.1%-99% vs US avg
x
Recent Births
25.7%+344% vs US avg
x
Smartphone Only
0.0%
x

People & Community key statistics

Population statistics
Population
Population87,775
Median age27.0
Poverty rate23.3%
Demographics statistics
Demographics
White63.7%
Hispanic43.8%
Black5.2%
Asian1.8%
Foreign-born34.0%