Postal Letter - Does the united states postal service do mail on sundays?

Does the united states postal service do mail on sundays?

Not, delivering packages to peoples houses, but going from one post office facility to the next.

nope sorry only mon thru saturday
Not since the 1950's.
Yes, the post office moves mail seven days a week. During the middle of the night, also.
There are still Sunday collections, where collectors go from station to station emptying the collection boxes and taking the collected mail to the processing facility. Haven't done it in almost 30 years, back in my days as a sub carrier.
Yes. The mail does get moved from post office to post office on Sundays. Thanks mainly to FedEx. FedEx is the largest carrier of mail. More than the Post Office if you can believe it.
The USPS works 24 hrs a day 7 days a week including holidays. And we even deliver mail to peoples houses on Sundays and Holidays, but only Express Mail. The person above me is wrong. FedEx can't deliver more mail than we do because they get their mail from US!!. Most of our mail is sent by TRUCK not by FedEx's airplanes.
Yes they do. Lot's of it to. If it didn't move on weekends and Sundays then you wouldn't get mail on Monday. As for Fed Ex, there's no way they move more mail than USPS. Especially since they rely so heavily on the USPS to move their letters.