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Postal Encyclopedia

ZIP+4

Updated 2026-07-24

Enhanced ZIP Code

Addressing & Lists

A nine-digit ZIP Code that identifies a smaller delivery segment and supports accurate routing, barcoding, and automation.

Definition reviewed 2026-07-24. Plavidian reference, written from the USPS Domestic Mail Manual. Final mail classification, postage, and preparation are confirmed after list processing and production review.

Related terms in Addressing & Lists

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