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U.S. ZIP Codes Database 2026

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Middlesex County ZIP Codes

Browse all ZIP Codes, cities, and associated area codes registered in Middlesex County.

County State ZIP Code City Area Codes
Middlesex County MA 01719 Boxborough 351, 978
Middlesex County MA 01720 Acton 351, 978
Middlesex County MA 01721 Ashland 508, 774
Middlesex County MA 01730 Bedford 339, 351, 781, 978
Middlesex County MA 01731 Hanscom AFB 339, 351, 781, 978
Middlesex County MA 01741 Carlisle 339, 351, 781, 978
Middlesex County MA 01742 Concord 339, 351, 781, 978
Middlesex County MA 01746 Holliston 508, 774
Middlesex County MA 01748 Hopkinton 508, 774
Middlesex County MA 01749 Hudson 351, 508, 774, 978
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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.