Last week the Postal Service posted a proposed rule in the Federal Register to revise the section of the Domestic Mail Manual that involves postmarking. The purpose of the rule, entitled “Postmarks and Postal Possession,” is to educate the public about postmarks. It discusses the history of postmarks, how they’re applied, how they’re used by government agencies and the private sector, and so on.
But all of this information serves primarily as background. The main purpose of the rule is to inform customers that they can no longer expect a postmark to show the date a piece was mailed.
The Postal Service says the DMM revision “does not signal and would not effect a change in postmarking procedures.” Instead, the Postal Service seeks to make customers aware that “the postmark date does not inherently or necessarily align with the date on which the Postal Service first accepted possession of a mailpiece.”
In other words, up till now, it’s been understood that date on the postmark is the date a piece was mailed, so long as it was deposited before the last collection, as indicated by signage at the post office or on the collection box. From now on, one can no longer make this assumption.
Nearly half of single-piece First Class Mail may end up being postmarked a day (or more) after the mail was sent at the post office, dropped in a collection box, or collected by a carrier. That makes the odds that a letter has a same-day postmark about 50-50.
Since 2021, the Postal Service has lowered the service standards for First Class mail two times, and it’s lowered the targets for on-time delivery as well. Historian Christopher Shaw, author of First Class:The U.S. Postal Service, Democracy, and the Corporate Threat, sums it up like this: “With the delivery delays and now the postmarks, it appears that the Postal Service is doing what it can to undermine First Class mail.”
The postmark is widely used as a deadline for legal purposes like tax documents, business contracts, and election ballots. The end of same-day postmarking will thus have far-reaching consequences.
Postmarking and the RTO
This revision of the DMM has become necessary because the Postal Service is implementing an initiative called Regional Transportation Optimization as part of its Delivering for American Plan.
Traditionally, mail is transported from processing centers to post offices in the morning and then collected at post offices in the late afternoon or early evening for transport to the processing center.
Under the RTO initiative, the afternoon collection is eliminated, so the mail sits in the back of the post office overnight (as seen on the right), to be collected the next morning, when the day’s mail is dropped off. The RTO thus adds a day to delivery times, so earlier this year the Postal Service changed its service standards to reflect the extra day. But the RTO will impact postmarking as well; hence the proposed rule.
Postmarks are usually applied by automation equipment when the mail first arrives at a processing center. Since that scan typically happens on the same day that the piece was sent, the postmark has been a reliable indication of the date sent.
Under the RTO, however, senders and recipients of mail and packages will no longer be able to assume that the date on the postmark is the date that the piece was actually sent. In many cases, the postmark will show a date that is one day later, sometimes more.
Mail sent Monday through Friday at a RTO office won’t be postmarked until the next day. Mail sent on a Saturday won’t be collected until Monday morning, and it won’t be scanned until Monday afternoon or evening, so the postmark will be two days after it was sent. If a piece is sent on a Saturday before a Monday holiday, it may not be collected, processed and postmarked until Tuesday — a gap of three days.
The potential problems are made worse by the fact that thus far the Postal Service has done almost nothing to inform customers about when they can expect their mail to be postmarked and if their post office is an RTO office. The proposed rule is intended to improve notification, but how far can a Federal Register notice go, especially when it says nothing about how notification will improve beyond the notice? The notice fails to address any of the practical questions raised by the RTO’s impact on postmarking.
The timing of the postmark
In its filing for the Federal Register, the Postal Service downplays the significance of the postmark changes by saying the proposal “does not signal and would not effect a change in postmarking procedures; postmarks will continue to be applied to Single-Piece First Class Mail pieces, both letter-shaped and flat-shaped, in the same manner and to the same extent as before.”
When the Postal Service provided a FAQ page about the change in service standards earlier this year, it didn’t even mention the RTO and the postmark issues. In July, the Postal Service updated the FAQ sheet to add some information about the RTO and postmarking.
According to the updated FAQ, the Postal Service “is not changing our postmarking practices.” It will continue to cancel single-piece mail on its automation equipment in processing facilities “in the same manner and to the same extent as before.” If customers want to ensure that a mail piece is postmarked on the day it is sent, they can continue to bring the mail piece to the counter at the post office and request a manual cancellation.
“What may change,” says the FAQ page, “is the timing of the postmark applied in those processing facilities. Some mail and packages will not reach our processing machines until the day after they are collected by a carrier or dropped off at a Post Office.”
In order to ensure a same-day postmark, the sender will need to make a special request to have the letter postmarked at the retail window. If further proof is needed, the sender can pay an extra fee for a Certificate of Mailing ($2.40) or Certified Mail ($5.30). On some days, like Tax Day and Election Day, the sender may also need to wait in a long line at the post office in order to get a postmark or certification.
A little history
The postmark was introduced in 1661 by English Postmaster General Henry Bishop to show origin date and prevent mail delays. The Bishop mark was a simple handstamp showing the day and month (abbreviated to two letters) when the piece was sent.
Handstamps were the main form of postmarking until the 1870s, when automated processing and mechanical postmarking were introduced. Now most mail is cancelled with a sprayed-on ink jet mark at the processing center.
The handstamp is still available at post offices, but a customer must request it at the retail window when the mailpiece is tendered for mailing. This, along with mailing the piece certified, is about the only way to ensure that the date on the postmark aligns with the date on which the Postal Service first accepted possession of the mailpiece.
Currently, the main difference between the handstamp at the post office and automated cancelling at a processing center is that the location on the postmark is likely to be that of the processing center, not the origin post office – a minor matter to some, but an insult to civic pride for others, as the New York Times once reported.
But the date on the postmark hasn’t been a significant issue in the past because the postmark at a processing center has nearly always occurred in the evening of the day on which the piece was mailed.
The importance of same-day postmarking is illustrated by the fact that the Postal Service has a policy of what it calls “rollover” time (as explained in the Federal Register notice).
In those instances when a mail piece arrives at the processing center too late to be scanned on the same day, the Postal Service will have its processing machines apply a cancellation mark backdated to the date of mailing, even if the application of the postmark takes place after midnight (i.e., the next day).
The end of same-day postmarking for much of the mail will thus represent a change of historic magnitude. Most significant changes have involved the technology of the postmark. This one involves the timing — it’s not about how but when. This may be one of the biggest things to happen to postmarks since the Bishop mark was first introduced three and half centuries ago.
Postmarks are “really small pieces of history,” observes postmark collector Evan Kalish. “This mail-piece was in X place on Y date, and the postmark proves it.” Over the past fifteen years, Kalish has collected these “pieces of history” at over 12,000 post offices, as documented on his website Postlandia. He’s not alone in his appreciation of postmarks. The Post Mark Collectors Club has 400 members, and its museum houses the world’s largest collection of postmarks and a research library with references in postal history. There’s more about postmark history on the National Postal Museum and Linn’s Stamp News.
The scope of the RTO
The termination of afternoon collections under the RTO applies to post offices located more than 50 miles from one of the nation’s 60 Regional Processing & Distribution Centers (RPDC). Offices within 50 miles of a RPDC are generally excluded and will continue to receive the afternoon collection, so they won’t experience the postmark issue.
Since the RPDC mega-facilities are mostly in metropolitan centers, the RTO hits low-volume rural post offices the most — an issue examined at length by the Office of Inspector General and the Postal Regulatory Commission in its advisory opinion about the DFA (also discussed in my comments to the PRC).
But there are many urban areas outside the 50-mile radius, and they handle a significant amount of outgoing mail volume that will be impacted by RTO.
It should also be noted that recipients of mail sent from a RTO post office will experience the one-day delay, whether they’re in a RTO ZIP or not.
As of July 26, 2025, the RTO had been implemented at about 11,000 post offices. A list of these impacted ZIP Codes, shared with the PRC on August 1, 2025, can be found on the PRC website here; our version with post office addresses, as well as the corresponding RPDCs (in the original plan shared with the PRC), is here. The lists include the RTO implementations, which began in February 2025, as well as those that fell under the pilot program, Local Transportation Optimization (LTO), which began in October 2023. The Postal Service’s list, it should be noted, contains about 2,200 post offices located less than 50 miles from their RPDC. It’s not clear if this is due to an error or some other explanation.
UPDATE SEPT 2, 2025: In its filing today on the status of RTO implementations, the Postal Service acknowledged that “Due to an inadvertent oversight while generating the previous four reports, 2,327 ZIP Codes were incorrectly identified as RTO activated.” As of August 23, 2025, the RTO had been implemented in 9,504 ZIP Codes. The corrected list can be downloaded from the PRC website here; our expanded version of the list is here.
Here’s a map of the implementations as of August 23, 2025, color-coded by what the Postal Service calls “campus sites.” (Zoom in or go here for a full-page version.)
When the RTO plan is fully implemented over the coming months, about 24,413 of the country’s 33,700 post officers will no longer have an afternoon collection (Advisory Opinion, p. 115). Anything sent at these post offices will be subject to the postmark problem. (A planning-stage list of the impacted offices, based on data shared by the Postal Service with the PRC, is here; maps based on this list are here.)
About 47 percent of single-piece mail volume will originate in ZIPs subject to the RTO. (That estimate is based on volume and population data provided by the Postal Service for the advisory opinion). In 2024, single-piece First Class Mail volume was 10.7 billion. Under the RTO, something on the order of 5 billion pieces of mail would not get a same-day postmark. (There are more details about population and ZIP codes impacts by Congressional district and states here.)
It’s also possible that the postmark issue will encompass even more mail. During the PRC’s advisory opinion, the Postal Service said it might curtail weekend processing to save money. In response to an interrogatory from longtime postal expert Douglas Carlson, the Postal Service said Sundays and holidays will no longer be included in service standard calculations, which, among other things, would allow the Postal Service to “keep the Saturday night processing where appropriate, or alternately to reduce weekend and/or holiday processing and transit where appropriate to capture workhours.” If reducing weekend processing became widespread, it would virtually eliminate same-day postmarks for mail sent on a Saturday from any post office, RTO or not.
Notifying customers
In his brief for the PRC’s advisory opinion, Carlson pointed out that “Surely when customers have a postmark deadline to meet, if they make the safe assumption that their mail will eventually be delivered, the postmark date is the single most important event.”
Carlson urged the Postal Service to do everything it could to ensure that customers understood the nature of the changes being implemented. For example, the Postal Service should take steps to inform customers at the point of service whether their mailing would be subject to the RTO delay. Carlson also urged the Postal Service to modify the signs on collection boxes to indicate not just when the mail would be collected (as these signs do now) but when it would be postmarked. That also goes for the Last Collection Times provided on the Find USPS Locations website.
Following Carlson’s suggestions, in its advisory opinion the PRC “strongly encourages the Postal Service to seek out ways to clearly communicate with customers this change and how it affects postmarking and delivery expectations for mailpieces.”
Although the RTO has been implemented at thousands of post offices already, the notification to customers has thus far been minimal.
Signs have been posted at some post offices stating simply that new service standards went into effect on April 1, but the posting says nothing about the RTO. Instead, the notice provides a QR code that customers can scan on their phones (assuming they know how) to get more information.
The QR code sends one to a page on the USPS website about the Delivering for America plan. If one digs through the overview, one finds a section on the new service standards where there are links to a press release, fact sheet, FAQ page, service standards map, and service commitment page showing when to expect a mailpiece to be delivered. Only the recently updated FAQ page has any information about the RTO postmark issue.
Aside from sharing a list of RTO implementations with the PRC — which is extremely difficult to find on the PRC website (it’s here) — the Postal Service has posted nothing about which post offices will be subject to the RTO and where the RTO has already been implemented. When when you mail something, you can’t assume that it will be postmarked on the same day you sent it.
The mailbox rule: timely mailed, timely filed
In tax law, contract law, and other contexts, there’s a concept called “timely mailing treated as timely filing.” This essentially means that the date a document or payment is mailed is considered the date it was filed or paid, even if it is received by the recipient after the actual due date.
The concept is sometimes referred to as the mailbox rule or the posting rule. Under the mailbox rule, as codified by federal regulations at 27 CFR § 70.305, “an acceptance is valid and a contract is formed the moment the offeree mails or dispatches their acceptance, not when the offeror receives it.”
The postmark is the most common method for proving the date filed. The term “postmark” is cited several times in U.S. Code with reference to such matters as absentee ballots collected at any overseas location for members of the armed services; drug patent applications; IRS mailings; appealing veterans benefits; and voting regulations.
Even the Postal Service and Postal Regulatory Commission use the postmark as a deadline. The statute on post office appeals, 39 USC 404, states that an appeal over a post office closure, sent by mail, must be received by the Commission within 30 days of when the discontinuance notice was posted. The date on the postmark on the envelope containing the appeal determines whether the appeal is acceptable.
That’s not an inconsequential matter. In 2013, the PRC dismissed the appeal of the closing of the Franklin Station post office in Somerset County, New Jersey, simply because the appeal letter was postmarked one day after the deadline.
The postmark is ubiquitous in federal regulations. A search of the U.S. Code of Federal Regulations indicates that “postmark” appears 8,771 times. The references encompass numerous government agencies and typically involve administrative procedures, litigation, assessments of penalties, etc.
As the Postal Service observes in the Federal Register filing, the date on the postmark is used by numerous government agencies for purposes of deadlines.
The federal court system usually uses the date a document is received, but many state courts use the date the document was sent — as indicated by the postmark.
With respect to taxes, 26 U.S.C. § 7502(a) states that where tax documents and payments to the Internal Revenue Service are sent by mail and are delivered after the prescribed due date, the date of the “United States postmark stamped on the cover in which such return, claim, statement, or other document, or payment, is mailed shall be deemed to be the date of delivery or the date of payment, as the case may be.”
“Similar postmarking provisions,” the Postal Service notes, “exist across a broad spectrum of state laws and regulations.”
The postmark is also used in the private sector by entities like banks, insurers, and utility companies when determining if a bill payment was mailed on time, and for other purposes as well. Late payments may result in additional charges, cancelled insurance policies, and myriad other problems.
Issues for voting by mail
If one searches Google for the phrase “must be postmarked by,” the first twenty-five pages of results consist almost entirely of references to voting by mail.
As of June 2025, seventeen states, as well as the District of Columbia, allow mail ballots to arrive after Election Day so long as they are postmarked by Election Day: Alaska, California, Illinois, Kansas, Maryland, Massachusetts, Mississippi, Nevada, New Jersey, New York, North Dakota, Ohio, Oregon, Texas, Virginia, Washington, and West Virginia. Some states use the postmark to for voter registration forms as well.
President Trump, it may be noted, has issued an executive order that would disallow absentee ballots received after Election Day in federal elections. The order has already created confusion among election officials, and some provisions may be struck down.
The Postal Service’s FAQ sheet acknowledges that under the RTO “a ballot envelope traveling through the processing network may receive a postmark the day after it is collected by the Postal Service.”
In order to avoid problems, the Postal Service says that, as with any other mail piece, “voters may request that their ballot envelope be hand-cancelled when they bring their mail into any of our retail locations.” The Postal Service also encourages voters to mail ballots a week before the election day, so “the timing of the postmark should not be an issue.”
Additionally, during even-numbered years (with regularly scheduled general elections for federal office in November), the Postal Service will still hand-cancel postage on ballot mail being turned around locally as part of its “extraordinary measures” for elections.
None of these measures, however, will deal with the problem faced by election offices that use the postmark as the deadline. There will be no way of knowing if a machine-scanned ballot was postmarked on the day it was sent or the day after. The voter may believe the ballot was sent on time, but the election office may see a postmark that’s a day late, rendering the ballot or registration invalid.
(There’s more about election policies related to postmarking on the website of the National Conference of State Legislatures, and some of the problems with using postmarks in elections are noted in this 2020 CNN article.)
Submitting comments
In developing the Federal Register notice, the Postal Service conferred with industry mailers, private sector representatives, and state election officials, to better understand postmarks and postmark dates are being used. As with any proposed rulemaking, the FR notice invites the public to comment about its concerns.
One may mail or deliver written comments to the Director, Product Classification, U.S. Postal Service, 475 L’Enfant Plaza SW, Room 4446, Washington, DC 20260-3436. Email comments, containing the name and address of the commenter, may be sent to PCFederalRegister@usps.gov, with a subject line of “Postmarks and Postal Possession.”
Comments must be received on or before September 11, 2025. That’s “received on or before,” not “postmarked by.”
For more information, see the Federal Register posting.
There’s more about the RTO and the PRC’s advisory opinion on our dashboard on the docket.
— Steve Hutkins
(Featured image: 1913 postmark; Source: Linn’s Stamp News)