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
All states and U.S. territories
Maps and coordinates
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 21720 Cavetown Washington County 240
MD 21721 Chewsville Washington County 240
MD 21722 Clear Spring Washington County 223, 227, 240, 301, 304, 681, 717
MD 21723 Cooksville Howard County 410, 443, 667
MD 21727 Emmitsburg Frederick County 227, 240, 301, 410, 443, 667
MD 21733 Fairplay Washington County 227, 240, 301
MD 21734 Funkstown Washington County 227, 240, 301
MD 21737 Glenelg Howard County 227, 240, 301, 410, 443, 667
MD 21738 Glenwood Howard County 410, 443, 667
MD 21740 Hagerstown Washington County 223, 227, 240, 301, 717
Page 52 of 63

Geographic Map of Maryland

Postal context

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.