GLOSSARY
Undeliverable as addressed
By Justin Winter · Updated August 28, 2026
USPS’s classification for a piece that cannot be delivered to the address written on it — the umbrella term behind most returned mail.
Undeliverable as addressed (UAA) covers wrong or incomplete addresses, vacant addresses, recipients who have moved with no forwarding order, and refusals. What happens next depends on the class and on any ancillary service endorsement.
UAA is the practical argument for validating addresses before printing: most of it is preventable at the data layer, not in the mailroom.
See also
- Return to sender — A mailpiece sent back to the sender because it could not be delivered, was refused, or went unclaimed.
- Delivery Point Validation — A USPS check that confirms an address is a real, individually deliverable delivery point — down to the apartment or suite.
- Mail Recovery Center — The USPS "dead mail" office where undeliverable mail goes when it also cannot be returned to the sender.
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