No mail delivery Monday, however if your local PO has one of those priority mail computerized kiosks, you can weigh and print postage, and pay for it with a credit card, and deposit the item in the special box next to the computer station...any items handled this way over the weekend would then go out the first AM mail on Tuesday morning...you can pretty much mail anything that will go in the largest priority mail square box or for that matter any box that will fit the drop (it's quite large) as long as it has priority mail sticker on it and postage from the computerized kiosk...