U.S. postal lookup

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.

42,735 verified records
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State directory

Maryland ZIP Codes

Complete postal directory, details, and geographic map for the State of Maryland.

State ZIP Code City County Area Codes
MD 20634 Great Mills St. Mary's County 227, 240, 301
MD 20635 Helen St Mary's County 240
MD 20636 Hollywood St. Mary's County 227, 240, 301, 410, 443, 667
MD 20637 Hughesville Charles County 227, 240, 301, 410, 443, 667
MD 20639 Huntingtown Calvert County 227, 240, 301, 410, 443, 667
MD 20640 Indian Head Charles County 227, 240, 301
MD 20643 Ironsides Charles County 240
MD 20645 Issue Charles County 227, 240, 301
MD 20646 La Plata Charles County 227, 240, 301
MD 20650 Leonardtown St. Mary's County 227, 240, 301
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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.