ZIP code
78666
San Marcos, TX
78666 covers San Marcos in Hays County, with 87,775 people in the ACS 2023 estimate.
Figures are for the Census ZIP Code Tabulation Area (ZCTA), which is not the same as a USPS ZIP code. A PO Box or unique ZIP may have no ZCTA and no demographics. Methodology
U.S. Census Bureau, ACS 2019–2023 5-year (vintage 2023). Geography: ZCTA 78666. Methodology
ZIP code map of 78666
About ZIP code 78666
More enterprise fields
Commercial ZIP directory · not ACS
Commercial ZIP directory population_count for ZCTA 78666. Not ACS. Methodology
People in 78666
Race
- White47,756
- Black or African American5,484
- American Indian or Alaska Native836
- Asian2,134
- Native Hawaiian and Pacific Islander82
- Other race11,737
- Two or more races18,555
Hispanic or Latino (any race): 36,770
Age
- Under 108,037
- 10 to 1915,178
- 20 to 2928,111
- 30 to 399,533
- 40 to 496,809
- 50 to 596,732
- 60 to 696,353
- 70 to 793,960
- 80 and older1,871
Income and housing in 78666
Education
- High school graduate89.3%
- Bachelor's degree34.6%
- Graduate degree14.1%
Places covering 78666
Cities and places — Population overlap
Share of this ZIP/ZCTA’s population located within each place, based on ZIP Code Database place-overlap data. This is a population measure, not land-area overlap or the Census-place population.
- San Marcos78.0%
- Redwood4.6%
- Canyon Lake0.1%
- Kyle0.0%
- Wimberley0.0%
ZIP Code Database place-overlap table, field percent_of_zip_population_in_place, keyed by place_geoid. Not ACS 2019–2023. Overlap vintage is the shipped overlap table and is separate from ACS. Methodology
Counties — Population overlap
Share of this ZIP/ZCTA’s population located within each county, based on ZIP Code Database county-overlap data. This is a population measure, not land-area overlap or the Census county population.
- Hays County91.4%
- Guadalupe County7.0%
- Caldwell County1.4%
- Comal County0.2%
ZIP Code Database county-overlap table, field percent_of_zip_population_in_county, keyed by county_geoid. Not ACS 2019–2023. Overlap vintage is the shipped overlap table and is separate from ACS. Methodology
17.3% of this ZIP is outside city limits (a real overlap row, not missing data).
Population history for 78666
Hover the chart or read the table below (Year | ACS | IRS).
| Year | ACS population | IRS population |
|---|---|---|
| 2005 | 37,710 | |
| 2006 | 36,999 | |
| 2007 | 39,878 | |
| 2008 | 38,365 | |
| 2009 | 39,393 | |
| 2010 | 40,152 | |
| 2011 | 61,953 | 41,570 |
| 2012 | 63,255 | 42,400 |
| 2013 | 66,027 | 44,040 |
| 2014 | 68,704 | 46,690 |
| 2015 | 72,866 | 48,200 |
| 2016 | 75,968 | 48,940 |
| 2017 | 77,355 | 50,250 |
| 2018 | 79,276 | 50,900 |
| 2019 | 82,923 | 53,690 |
| 2020 | 81,844 | 56,560 |
| 2021 | 83,858 | 57,970 |
| 2022 | 86,530 | 59,940 |
| 2023 | 87,775 |
ACS: U.S. Census Bureau American Community Survey 5-year estimates. IRS: Statistics of Income ZIP Code data.
ZIP codes near 78666
12 nearest ZIP centroids (any distance)
- 78655Martindale10.1 miPop 3,687 · Income $48,409
- 78656Maxwell10.7 miPop 2,953 · Income $78,058
- 78670Staples11.5 miPop 178 · Income $76,591
- 78640Kyle12.5 miPop 71,460 · Income $88,533
- 78130New Braunfels13.9 miPop 95,787 · Income $84,426
- 78622Fentress14.1 miPop 353 · Income $72,941
- 78135New Braunfels14.6 miPop — · Income —
- 78623Fischer14.8 miPop 1,575 · Income $122,143
- 78132New Braunfels15.0 miPop 40,383 · Income $126,934
- 78676Wimberley15.1 miPop 15,896 · Income $86,819
- 78133Canyon Lake16.0 miPop 21,830 · Income $80,777
- 78610Buda16.2 miPop 46,685 · Income $110,417
ZIP centroids within 2 miles
No other ZIP codes within 2 miles of 78666, measured by Census internal-point centroids. Try a wider radius.
ZIPs within 2 miles of this place
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ZIP code 78666 FAQ
- What city is ZIP code 78666 in?
- 78666 is in San Marcos, TX.
- What county is 78666 in?
- 78666 is in Hays County.
- What is the median household income in 78666?
- The median household income in 78666 is $55,478.
- Which ZIP codes are near 78666?
- Use the radius tool on this page to list ZIP codes within a chosen distance of 78666.