Lost in the Mail: USPS Clarifies What a Postmark Does—and Does Not—Mean

For generations, a postmark has served as a quiet but powerful signal. In business, legal filings, and everyday transactions, it has commonly been treated as evidence not just that a letter passed through the postal system, but that it had been received by the Postal Service on a particular date. That assumption is now explicitly challenged by new guidance from the United States Postal Service.

Effective December 24, 2025, the Postal Service added a new section to the Domestic Mail Manual (DMM) titled “Postmarks and Postal Possession.” The section defines what qualifies as a postmark, explains when postmarks are applied, and outlines how customers may obtain proof of the date the Postal Service accepted custody of their mail.

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Under the clarified language, a postmark confirms only that a mailpiece was in the possession of the Postal Service on the date shown. It does not necessarily indicate the first day the Postal Service had the item. At the same time, the guidance makes clear that the absence of a postmark does not mean a mailpiece was never accepted at all, since the Postal Service does not postmark every piece of mail in the ordinary course of operations.

In other words, a postmark may reflect a moment during a mailpiece’s journey—but not its beginning.

Recognizing that many customers rely on dates for compliance, deadlines, and record-keeping, the Postal Service outlines ways to ensure closer alignment between a postmark and the actual date of mailing. Customers may request a manual (local) postmark at no additional charge when presenting a mailpiece at a post office counter. Because this postmark is applied upon acceptance, its date aligns with the day the Postal Service first took possession of the mail. Those submitting large volumes—50 or more pieces—are advised to coordinate in advance.

Similarly, labels generated at the retail counter, known as PVI labels, reflect the date on which postage is paid and the mailpiece is tendered simultaneously. By contrast, pre-printed postage—such as Click-N-Ship labels, self-service kiosk receipts, or meter strips—shows only the date postage was purchased or printed. These markings, the guidance notes, do not demonstrate when the Postal Service accepted the mail, or whether acceptance occurred on that date.

For customers who require documentation of acceptance rather than inference, the Postal Service points to existing services. A Certificate of Mailing provides evidence that individual mailpieces were presented for mailing, while Certified Mail and Registered Mail include mailing receipts that serve a similar function.

The Postal Service insists that “this new language in the DMM does not change any existing postal operations or postmarking practices.” If that is the case, the clarification raises a different question: when, exactly, the postmark came to be understood as proof of receipt in the first place.

Las Cruces Digest is left to conclude that the presumed relationship between a postmark and the date of postal acceptance has—somewhere, sometime—been lost in the mail.