Following former President Jimmy Carter’s death on Dec. 29, President Joe Biden declared Thursday, Jan. 9 as a National Day of Mourning in honor of the late centenarian leader.

By an executive order from Biden, all federal agencies will be closed Thursday. Most employees will get the day off, except for those most valuable to “national security efforts, defense, or other public need,” according to the order.

The closure includes agencies such as the United States Postal Service, meaning no USPS mail will be delivered on Thursday and all post offices will be closed.