Williamson County ZIP Codes
Williamson County is a county of Texas.
- ZIP codes
- 27
- Cities & towns
- 16
- Area codes
- 3
- Land area
- 1,116 sq mi
Every ZIP code in Williamson County
| ZIP code | City |
|---|---|
| 76527 | Florence |
| 76530 | Granger |
| 76537 | Jarrell |
| 76573 | Schwertner |
| 76574 | Taylor |
| 76578 | Thrall |
| 78613 | Cedar Park |
| 78615 | Coupland |
| 78626 | Georgetown |
| 78627 | Georgetown |
| 78628 | Georgetown |
| 78630 | Cedar Park |
| 78633 | Georgetown |
| 78634 | Hutto |
| 78641 | Leander |
| 78642 | Liberty Hill |
| 78646 | Leander |
| 78664 | Round Rock |
| 78665 | Round Rock |
| 78673 | Walburg |
| 78674 | Weir |
| 78680 | Round Rock |
| 78681 | Round Rock |
| 78682 | Round Rock |
| 78683 | Round Rock |
| 78717 | Austin |
| 78729 | Austin |
We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the Williamson County codes above are listed without a column we would have to invent.
Cities and towns in Williamson County
A further 2 places in Williamson County appear in the postal source without a page of its own; their codes are in the table above and each one links to its own page.
Area codes covering Williamson County
Telephone and postal boundaries are drawn by different bodies, so these codes overlap the county without matching its edges.
Where Williamson County's ZIP codes sit
- Reference points and footprint
- Not an official NANPA boundary
- Not a USPS delivery area
Scope every ZIP code recorded in Williamson County. Source GeoNames US postal codes (2026-07 postal dump), Census 2024 county Gazetteer (2024 Gazetteer) and geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot). Updated . The outline is a convex envelope of ZIP reference points, not a jurisdiction boundary.