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

Iowa ZIP Codes

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

State	ZIP Code	City	County	Area Codes
IA	50156	Madrid	Boone County	`515`
IA	50157	Malcom	Poweshiek County	`641`
IA	50158	Marshalltown	Marshall County	`641`
IA	50160	Martensdale	Warren County	`515, 641`
IA	50161	Maxwell	Story County	`515, 641`
IA	50162	Melbourne	Marshall County	`641`
IA	50163	Melcher Dallas	Marion County	`641`
IA	50164	Menlo	Guthrie County	`515, 641`
IA	50165	Millerton	Wayne County	`641`
IA	50166	Milo	Warren County	`515, 641`

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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.