Christmas became a federal holiday in the US officially in 1968 and is the only religious holiday recognized by the US government. Back in 1870, President Ulysses S. Grant named Christmas as one of the first federal holidays as a way of reducing absenteeism. However, federal holidays only extended to federal employees working in the District of Columbia during that time. It wasn’t until the Monday Holiday Law was passed by Congress in 1968 during Lyndon B. Johnson’s presidency that Christmas was deemed a federal holiday, in which all federal employees nationwide received the day off on 25 December of each year.
More about the history of Christmas in the US: