COLUMBIA, S.C. (WOLO)– Holiday planners listen up, if you’re using the U.S. Postal Service for shipping, here’s what you need to know. For delivery by Christmas Day in the contiguous United States, USPS recommends that packages are sent no later than December 21. That’s for priority mail express service, which is faster and usually costs more. Less expensive options, like first-class mail and ground service must go out by December 18. First class mail must go out by December 18, and the cut off for ground service is December 16. Categories: News Tags: U.S. Postal Service