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Why are there no ZIP Codes in the Geographic Names Information System Database?

The Geographic Names Information System (GNIS) contains named communities--both incorporated and unincorporated--but these communities do not necessarily correspond to ZIP Code areas. ZIP Codes are unofficial entities developed and maintained by the U.S. Postal Service solely for delivering mail.

ZIP Code areas are named by the Post Office for the preferred location within that zone, which might or might not have any reference to the local community or its boundaries. Despite ZIP Codes appearing to have a geographic location, they might not correspond to a physical location.

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