USPS Quietly Changed Postmarks—Here’s Why Montanans Should Care

The United States Postal Service (USPS) has made a change to its postmarks which went into effect on December 24, 2025, and will affect a lot of mail that is sent in Montana, especially in rural areas.  

What Changed With USPS Postmarks

The change involves when postmarks are now applied to pieces of mail. Postmarks used to be put on mail when it was collected by the post office, but now they are not put on pieces of mail until they are processed by the mail facility. 

Why the Change Matters for Montana

This may not seem like a big change, but it is when you consider pieces of mail that must be somewhere by a specific date, like a bill, mail-in ballot, or an IRS tax return. According to AARP, date differences are likely to “become more common” as this change is rolled out. 

READ MORE: What the USPS’s Lobby Overhaul Means for Montana Mail Customers

There are a few tips that can ensure your mail is postmarked promptly.  

Make sure you mail important timely materials early.  

READ MORE: 7 Things You Can't Legally Mail in Montana

You can request a manual postmark when you drop off your mail at a post office. This makes sure that the date matches when your mail was accepted by the post office.  

Send your mail by registered or certified mail, which includes receipts and tracking information.  

Customers can request a certificate of mailing. This provides proof of when something was mailed. 

Keep these changes in mind when sending your ballots or your tax returns through the mail. If the postmark says a later date than what is accepted, your ballot may be rejected, or you may be subjected to fines from the IRS.