In which county is ZIP code 78664 located?

ZIP 78664 is listed under Williamson County, TX.

When was this page updated?

This page was updated on 2026-01-08.

ZIP Code 78664: Round Rock, TX

ZIP: 78664

County: Williamson County

Coordinates: 30.51450, -97.66800

ZIP Type: Standard

Time Zone: Central Time (CT)

Explore detailed information for ZIP code 78664 in Round Rock, TX. We include verified county details for Williamson County plus key geographic references used for mapping and logistics.

Primary City	Round Rock
ZIP Code	78664
County	Williamson County
State	TX
Latitude / Longitude	30.51450, -97.66800
ZIP Type	Standard
Time Zone	Central Time (CT)
Data Updated	2026-01-08

Maps & Useful Links

Open in Maps: Google Maps · OpenStreetMap

These links show the approximate center point for ZIP 78664 (not an exact boundary).

Geographic & Administrative Context

For mapping and verification, 78664 is commonly represented around 30.51450, -97.66800. These coordinates help identify the general area within Williamson County, TX.

Local Coverage Notes

ZIP codes can cover multiple neighborhoods and unincorporated areas. Use ZIP 78664 for mail delivery and general location reference in Williamson County, TX.

Coverage may include nearby neighborhoods and adjacent unincorporated areas commonly associated with Round Rock.

Related ZIP Codes (Nearby)

Explore other postal codes near Round Rock within TX.

Frequently Asked Questions

What is the primary city for ZIP code 78664?

The primary city for this ZIP code is Round Rock, located in TX.

In which county is 78664 located?

ZIP code 78664 is situated within Williamson County, TX.

What are the coordinates for 78664?

The approximate center point is 30.51450 (Latitude) and -97.66800 (Longitude).

Is ZIP code 78664 active?

This page lists ZIP 78664 as Listed based on the latest refresh date shown above.

Does ZIP 78664 cover multiple areas?

Yes. Many ZIP codes cover multiple neighborhoods or nearby areas. For exact boundaries, use official mapping tools.

Methodology & Data Notes

How we build this page: We generate this page from a structured ZIP dataset and refresh key fields (city, county, and coordinates) during scheduled updates. Coordinates represent an approximate center point, not an official boundary map.
Sources: Public ZIP reference datasets and geographic coordinate references. If you use specific sources (e.g., USPS, Census), list them on your About/Methodology page.

Page updated: 2026-01-08