When George Washington was born, the date was February 11, 1731. You see, the United Kingdom of Great Britain was using the Julian Calendar back then. There is an issue with leap years with the Julian Calendar, so the calendar was always slowly getting more and more inaccurate. Also, in England and the colonies, New Year's Day was on March 25. Go figure.
Anyway, in 1750, the U.K. changed to the Gregorian Calendar and fixed things. New Year's Day was now in January. The calendar dates were adjusted 11 days, which meant that, retroactively, George Washington was born on February 22, 1732. But that was only the first time people screwed around with his birthday.
The federal government did try to do right by Washington in 1879 when they added a fifth national holiday. Washington's Birthday, February 22nd, was added to the list of New Year’s Day, Independence Day, Thanksgiving Day, and Christmas Day as national holidays. Other holidays were added later, until we have the ten we have today.
In 1971, the Uniform Monday Holiday Act went into effect, moving many of the holidays to Mondays instead of the proper or traditional day. Washington's Birthday was one of those. And, just like the government, they made it so it would never be right. The holiday falls on the third Monday in February, which means it can be as early as the 15th, and as late as the 21st. It will never be on the 22nd, which is when it actually is.
Some states used to celebrate Lincoln's Birthday on February 12th. Around half the states have state holidays honoring both Lincoln and Washington today. And, states can do that. Still, the federal holiday is, and has always been Washington's Birthday.
If your state celebrates more than just George Washington today, fine. Honor Lincoln and the other presidents that your state recognizes. But, there is a reason the federal holiday is simply Washington's Birthday. Don't forget to honor the man without whom we might very well not have this great nation.
George Washington. February 22, 1732 - December 14, 1799. First in war, first in peace, first in the hearts of his countrymen.