On Christmas Day, the United States Postal Service (USPS) is typically closed and no mail delivery or pickup services are available. However, the USPS does offer limited services on Christmas Eve, so it's possible to send a package on December 24th that will be delivered on December 25th if it meets certain criteria. To find out if the specific location you're sending from is open on Christmas Eve, you can check the USPS website or contact your local post office directly.