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U.S. ZIP Codes Database 2026

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St. Mary's County ZIP Codes

Browse all ZIP Codes, cities, and associated area codes registered in St. Mary's County.

County State ZIP Code City Area Codes
St. Mary's County MD 20630 Drayden 227, 240, 301
St. Mary's County MD 20634 Great Mills 227, 240, 301
St. Mary's County MD 20636 Hollywood 227, 240, 301, 410, 443, 667
St. Mary's County MD 20650 Leonardtown 227, 240, 301
St. Mary's County MD 20653 Lexington Park 227, 240, 301, 410, 443, 667
St. Mary's County MD 20656 Loveville 227, 240, 301
St. Mary's County MD 20659 Mechanicsville 227, 240, 301, 410, 443, 667
St. Mary's County MD 20660 Morganza 227, 240, 301
St. Mary's County MD 20667 Park Hall 227, 240, 301
St. Mary's County MD 20670 Patuxent River 227, 240, 301, 410, 443, 667
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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.