The United States is collectively mourning the loss of former President Jimmy Carter, with a National Day of Mourning designated for remembrance. On this day, various institutions, including all post offices, banks, and the federal government, will be closed. The New York Stock Exchange and other major markets will also remain shut in honor of Carter’s memory. Residents are advised to check local closures as services may be affected nationwide. Additionally, the IRS has announced an extension of tax deadlines in commemoration of this significant day.