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 60537 Millington LaSalle County 779, 815
IL 60538 Montgomery Kendall County 331, 630
IL 60539 Mooseheart Kane County 331, 630
IL 60540 Naperville DuPage County 331, 630
IL 60541 Newark Kendall County 331, 630, 779, 815
IL 60542 North Aurora Kane County 331, 630
IL 60543 Oswego Kendall County 331, 630
IL 60544 Plainfield Will County 331, 630, 779, 815
IL 60545 Plano Kendall County 331, 630, 779, 815
IL 60546 Riverside Cook County 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.