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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.

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St. Clair County ZIP Codes

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

County State ZIP Code City Area Codes
St. Clair County MI 48061 Port Huron 810
St. Clair County MI 48063 Columbus 586, 810
St. Clair County MI 48064 Casco 586, 810
St. Clair County MI 48074 Smiths Creek 810
St. Clair County MI 48079 Saint Clair 226, 519, 548, 586, 810
St. Clair County MI 48097 Yale 810
St. Clair County MO 64724 Appleton City 417, 660
St. Clair County MO 64738 Collins 417
St. Clair County MO 64763 Lowry City 417, 660
St. Clair County MO 64776 Osceola 417, 660
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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.