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 21155 Upperco Baltimore County 410, 443, 667
MD 21156 Upper Falls Baltimore County 410, 443, 667
MD 21157 Westminster Carroll County 410, 443, 667
MD 21158 Westminster Carroll County 223, 410, 443, 667, 717
MD 21160 Whiteford Harford County 223, 410, 443, 667, 717
MD 21161 White Hall Harford County 223, 410, 443, 667, 717
MD 21162 White Marsh Baltimore County 410, 443, 667
MD 21163 Woodstock Howard County 410, 443, 667
MD 21201 Baltimore Baltimore city 410, 443, 667
MD 21202 Baltimore Baltimore city 410, 443, 667
Page 32 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.