George Washington, "First In War, First In Peace, And First In The Hearts Of His Countrymen" if you're normal, or "a person who held human beings in bondage" if you're not, was born on February 22, 1732, according to the Gregorian Calendar. For most of American history, Americans celebrated his birthday around this time. The "President's Day" thing only started in 1971 under the Nixon Administration, and is a Bad Idea.
In 2001, Tom Tancredo and Roscoe Bartlett introduced legislation to change it back—although as you'll see below it's still legally Washington's Birthday; they wanted to force bureaucrats and the President to proclaim it that way—and the late Sam Francis wrote it up here:
The modern President's Day is supposed to honor ALL Presidents, including Millard Fillmore, Rutherford Hayes, both of the President Harrisons, and I supposed even the Bushes.
But as I say, it's really not President's Day: It's George Washington's Birthday: