What it is
The federal holiday's legal name is still Washington's Birthday, and the U.S. Code never says Presidents' Day. Most calendars, stores and states use Presidents' Day, and many treat it as a day to honor Abraham Lincoln as well.
Because it is the third Monday in February, it always falls between February 15 and 21. That means it never lands on Washington's actual birthday, February 22.
Is it a day off?
Federal offices, banks, schools in many districts and the stock market close. Many retailers run sales instead of closing. Fewer private employers give this day off than give Memorial Day or Labor Day.
History
Washington's Birthday became a holiday for federal offices in Washington, D.C., in 1879 and nationwide in 1885. The Uniform Monday Holiday Act moved it from February 22 to a Monday starting in 1971.