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U.S. ZIP Codes Database 2026

Search by ZIP code, city, county, or state and find clear postal details with maps, time zones, and area code data.

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Williamson County ZIP Codes

Browse all ZIP Codes, cities, and associated area codes registered in Williamson County.

County State ZIP Code City Area Codes
Williamson County TX 76574 Taylor 512, 737
Williamson County TX 76578 Thrall 512, 737
Williamson County TX 78613 Cedar Park 512, 737
Williamson County TX 78626 Georgetown 512, 737
Williamson County TX 78627 Georgetown 512
Williamson County TX 78628 Georgetown 512, 737
Williamson County TX 78630 Cedar Park 512
Williamson County TX 78633 Georgetown 254, 512, 737
Williamson County TX 78634 Hutto 512, 737
Williamson County TX 78641 Leander 512, 737, 830
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About U.S. ZIP Codes

ZIP codes are a United States Postal Service system introduced in 1963 to make mail routing more accurate and efficient. The standard format uses five digits, while ZIP+4 adds four more digits for a more precise delivery segment.

ZIP codes cover the United States, its territories, military mail routes, and other USPS delivery points. This directory organizes that data for practical lookup by ZIP code, city, county, and state.