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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 20674 Piney Point 227, 240, 301
St. Mary's County MD 20680 Ridge 227, 240, 301
St. Mary's County MD 20684 Saint Inigoes 227, 240, 301
St. Mary's County MD 20686 Saint Marys City 227, 240, 301
St. Mary's County MD 20687 Scotland 227, 240, 301
St. Mary's County MD 20690 Tall Timbers 227, 240, 301
St. Mary's County MD 20692 Valley Lee 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.