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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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Winnebago County ZIP Codes

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

County State ZIP Code City Area Codes
Winnebago County IL 61105 Rockford 815
Winnebago County IL 61106 Rockford 815
Winnebago County IL 61107 Rockford 779, 815
Winnebago County IL 61108 Rockford 779, 815
Winnebago County IL 61109 Rockford 779, 815
Winnebago County IL 61110 Rockford 815
Winnebago County IL 61111 Loves Park 779, 815
Winnebago County IL 61112 Rockford 779, 815
Winnebago County IL 61114 Rockford 779, 815
Winnebago County IL 61115 Machesney Park 779, 815
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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.