Here’s a handy link to the 2023 USPS Postal Holidays and LetterStream Holiday Schedule. We’ve also included important USPS early closing days which are not typically spelled out on the USPS Postal Holidays web page.
One more important mention; most USPS retail counters close early on both Christmas Eve and New Year’s Eve, so make sure you call ahead and/or plan accordingly. In conjunction, LetterStream will also be closing early on both of those days.