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Greater Austin Mission SocietyState of the City

Zip code · San Marcos

78666

78666 is a zip code in the San Marcos division of the Austin metro. This page gathers who lives here, from the Census Bureau, and the 53 congregations and 4 ministries the Greater Austin Mission Society knows of in and around it, with how each figure compares with the division and the metro.

Who lives here

  • Residents

    88,583 ±1,333

  • Median age

    26.9 ±0.6

  • Households

    33,949 ±943

  • Homes owned by the people living in them

    12,927 ±790

  • Homes rented

    21,022 ±1,043

  • Median household income

    $54,737 ±$3,230

Language spoken at home

Share of residents five and over.

  • English only

    72.1% ±1.9 points

  • Spanish

    24.6% ±1.9 points

  • Another language

    3.3% ±0.9 points

2026 edition, ACS 2020-2024, by ZIP Code Tabulation AreaZIP Code Tabulation Area (ZCTA)The Census Bureau's map of a postal zip code, built from census blocks, so the two can differ at the edges.More in the glossary

Who is already here

Congregations and ministries whose address is in 78666, or that sit within a mile of its centre, nearest first.

Congregations

Ministries

Our church database, 2026-10-16 · Our database, 2026-10-16. These are counts of our own records, not a survey, so they carry no margin of error; they are as complete as the database is.

How it compares

Residents per church

About 1,670, counting the 53 congregations whose address is in 78666

A little more than the San Marcos division's figure, and a little less than the figure across the fifteen divisions.

People cross zip lines to worship, so read this as the zip's share of congregations, not how many people each one serves.

  • Median age

    About the same as the San Marcos division's figure, and roughly two-thirds of the metro figure.

  • Median household income

    Roughly the same as the San Marcos division's figure, and about half of the metro figure.

  • Speaking only English at home

    About the same as the San Marcos division's figure, and about the same as the metro figure.

  • Speaking Spanish at home

    Roughly the same as the San Marcos division's figure, and roughly the same as the metro figure.

  • Speaking another language at home

    Roughly the same as the San Marcos division's figure, and roughly a third of the metro figure.

Census figures are for the ZIP Code Tabulation Area, the Census Bureau's approximation of the postal zip, which can differ at the edges. Each carries its margin of errorMargin of errorThe range, at 90 percent confidence, within which a survey figure's true value probably falls, so 1,000 ±100 likely means between 900 and 1,100.More in the glossary at 90 percent; a figure whose margin is wide is marked as a rough estimateA rough estimateA figure whose margin of error is more than about half the figure itself; a figure whose margin passes about two-thirds of it is not shown.More in the glossary, and one too uncertain to read is not shown. Comparisons are with the zip's own division and the metro, never with another zip.

78666 sits inside the San Marcos division, and its prayer guide covers these streets.

Pray for San MarcosSee San MarcosEvery record near 78666

What the numbers are telling us

The Greater Austin Mission Society writes about the church in this metro: what this data shows, what it does not, and what we think it asks of us. The letters are written for leaders here.

Read the letters