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 21133 Randallstown Baltimore County 410, 443, 667
MD 21136 Reisterstown Baltimore County 410, 443, 667
MD 21139 Riderwood Baltimore County 410
MD 21140 Riva Anne Arundel County 410, 443, 667
MD 21144 Severn Anne Arundel County 410, 443, 667
MD 21146 Severna Park Anne Arundel County 410, 443, 667
MD 21150 Simpsonville Howard County 410
MD 21152 Sparks Glencoe Baltimore County 410, 443, 667
MD 21153 Stevenson Baltimore County 410, 443, 667
MD 21154 Street Harford County 410, 443, 667
Page 31 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.