Christmas was formally recognized as a national U.S. holiday in 1870. Although it wasn't formally recognized until 1870, the holiday was celebrated by many states before that and has been celebrated by many other countries.
Christmas is a holiday with a mix of early Christian and pagan origins. Many modern religions celebrate Christmas on December 25 as the birthday of Jesus Christ. However, it may have had its start in an ancient Roman Winter Solstice festival held on that exact date each year. Early Christians didn't even recognize this time or the birth of Jesus as a cause for parties and celebrations, but a solemn occasion. It wasn't until about 1840 that the current practice of celebrating Christmas with merriment became popular.
In the 1870s, the government moved to start recognizing many state holidays as federal holidays. This move created the nation's first officially recognized national holidays, which provided federal employees in Washington, D.C. with these holidays off. Christmas was among the first five national holidays, including New Year's Day, George Washington's Birthday, Independence Day, Independence Day and Thanksgiving. It wasn't until 1968 that all federal employees, outside of Washington D.C., were officially give time off on these national holidays. By then, Christmas was considered a day off for most people to celebrate with their families.
Christmas is now a worldwide holiday, celebrated as both a religious and a secular event.