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 60204 Evanston 224
Cook County IL 60208 Evanston 224, 847
Cook County IL 60209 Evanston 224
Cook County IL 60290 Chicago 312
Cook County IL 60301 Oak Park 464, 708
Cook County IL 60302 Oak Park 464, 708, 773, 872
Cook County IL 60303 Oak Park 708
Cook County IL 60304 Oak Park 464, 708, 773, 872
Cook County IL 60305 River Forest 464, 708, 773, 872
Cook County IL 60402 Berwyn 464, 708
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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.