ZIP [Zone Improvement Plan] Codes designate mail delivery routes and areas.
There are three main parts of the 5-digit ZIP Code—the national area, the region or city, and the delivery area. The first digit represents the national area, the second and third digits represent the sectional center or large city post office, and the last two digits represent the area of the city or town.
Can the same ZIP Code exist in more than one state?
ZIP Codes are not drawn according to state boundaries, so dome do cross county and state boundaries. For example:
- 42223 spans Christian County, Kentucky, and Montgomery County, Tennessee;
- 97635 includes portions of Lake County, Oregon, and Modoc County, California; and
- 51023 and 51001 are in both Iowa and Nebraska.
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