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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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Caldwell County ZIP Codes

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

County State ZIP Code City Area Codes
Caldwell County TX 78655 Martindale 512, 737, 830
Caldwell County TX 78656 Maxwell 512, 737
Caldwell County TX 78661 Prairie Lea 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.