Question

Does USPS transit packages on Sunday?

Answer 1

Although the USPS local post offices are closed on Sunday the USPS is constantly delivering mail and sorting it at it's USPS sorting facilities.

So yes your mail is always in transit even on Sundays and holidays through the USPS sorting facilities that way when Monday comes around your mail will be able to reach your location.

The USPS sorting facilities are always open 24/7 around the clock and never close unless there's an emergency.

Answer 2

USPS is always constantly moving packages and letters through it's system both on holidays and even on Sundays.

The USPS has workers around the clock driving semis, flying airplanes and even working in it's sorting facilities 24 hours per day 7 days per week to keep packages and letters moving throughout it's system.

This allows your packages and letters to be delivered on the correct date.