Question

Is USPS mail still sorted on Sundays?

Does USPS still sort mail at their sorting Facilities on Sundays and even Holidays?

Answer 1

Although the actual post offices where you get your mail are closed on Sundays and Holidays the Sorting Facilities work around the clock 24 hours per day 7 days per week and I do believe it includes holidays as well.

So while the post office is closed your mail is still being processed through the sorting facilities even on a Sunday to get to it's destination.