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What county is ZIP code 78750 in?

Updated · Data: U.S. Census Bureau

ZIP code 78750 (Austin, TX) is mostly in Travis County (78.1% of its land), with parts in Williamson County.

Which counties is ZIP 78750 in?

CountyShare of land areaChart
Travis County78.1%
Williamson County21.9%

About 29,322 people live in this ZIP code area. Because it crosses a county line, the county depends on the street: check your address.

Is ZIP 78750 a Census ZIP code area?

Yes. A ZIP Code Tabulation Area (ZCTA) is the Census version of a ZIP code; its edges can differ from USPS delivery routes (ZIP code vs ZCTA). Look up another ZIP on the ZIP code to county lookup.

Sources: Census 2020 ZCTA-county relationship file; Gazetteer 2024; GeoNames (CC BY 4.0, post office name); ACS 2019-2023 5-year. Data as of November 1, 2026. Not affiliated with USPS or any government agency.

FAQ

Frequently asked questions

What county is ZIP code 78750 in?
ZIP code 78750 (Austin, TX) is mostly in Travis County (78.1% of its land), with parts in Williamson County.
Is ZIP 78750 in Williamson County?
Partly: about 21.9% of its land is in Williamson County.
What city is ZIP 78750?
The post office name is Austin.

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