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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 02476 Arlington 339, 617, 781, 857
Middlesex County MA 02477 Watertown 617
Middlesex County MA 02478 Belmont 339, 617, 781, 857
Middlesex County MA 02479 Waverley 617, 857
Middlesex County MA 02493 Weston 339, 508, 617, 774, 781, 857
Middlesex County MA 02495 Nonantum 617
Middlesex County NJ 07001 Avenel 732, 848, 908
Middlesex County NJ 07008 Carteret 347, 718, 732, 848, 908, 917, 929
Middlesex County NJ 07064 Port Reading 347, 718, 732, 848, 917, 929
Middlesex County NJ 07067 Colonia 732, 848
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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.