U.S. postal lookup

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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Cook County ZIP Codes

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

County State ZIP Code City Area Codes
Cook County IL 60611 Chicago 312, 872
Cook County IL 60612 Chicago 312, 773, 872
Cook County IL 60613 Chicago 773, 872
Cook County IL 60614 Chicago 312, 773, 872
Cook County IL 60615 Chicago 773, 872
Cook County IL 60616 Chicago 312, 773, 872
Cook County IL 60617 Chicago 219, 773, 872
Cook County IL 60618 Chicago 773, 872
Cook County IL 60619 Chicago 773, 872
Cook County IL 60620 Chicago 464, 708, 773, 872
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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.