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.

42,735 verified records

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State directory

Illinois ZIP Codes

Complete postal directory, details, and geographic map for the State of Illinois.

State	ZIP Code	City	County	Area Codes
IL	61377	Wenona	Marshall County	`309, 779, 815`
IL	61378	West Brooklyn	Lee County	`779, 815`
IL	61379	Wyanet	Bureau County	`309, 779, 815`
IL	61401	Galesburg	Knox County	`309`
IL	61402	Galesburg	Knox County	`309`
IL	61410	Abingdon	Knox County	`309`
IL	61411	Adair	McDonough County	`309`
IL	61412	Alexis	Warren County	`309`
IL	61413	Alpha	Henry County	`309`
IL	61414	Altona	Knox County	`309`

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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.