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What county is ZIP code 79031 in?

Updated · Data: U.S. Census Bureau

ZIP code 79031 (Earth, TX) is mostly in Lamb County (93.2% of its land), with parts in Castro County.

Which counties is ZIP 79031 in?

CountyShare of land areaChart
Lamb County93.2%
Castro County6.8%

About 1,213 people live in this ZIP code area. Because it crosses a county line, the county depends on the street: check your address.

Is ZIP 79031 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 79031 in?
ZIP code 79031 (Earth, TX) is mostly in Lamb County (93.2% of its land), with parts in Castro County.
Is ZIP 79031 in Castro County?
Partly: about 6.8% of its land is in Castro County.
What city is ZIP 79031?
The post office name is Earth.

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