George Washington, first President of the United States of America, was born on February 11, 1731, according to the Julian Calendar being observed by the Britsh Empire at the time of his birth. We now recognize February 22, 1732, as his birthday since the British have subsequently converted to the Gregorian Calendar.
Congress created a federal holiday honoring our first President in 1879. In 1971, the Uniform Monday Holiday Act shifted this holiday to the third Monday in February.
While colloquially known as “President’s Day” (and some States do officially use that term), the actual federal holiday honors only George Washington.