One might think it rather convenient that Evacuation Day is scheduled for the same date as St. Patrick's Day. However, the two dates in history do correspond.
What is Evacuation Day? I admit I did not know, either, until I read David McCullough's masterpiece, "1776." On March 17, 1776, the British evacuated Boston during the relative early days of the Revolutionary War. The story is a great one. The rebels pinned the British in Boston during the Winter of 1776 by transporting large guns from Fort Ticonderoga in upstate New York, sneaking the armory into what is now South Boston. The British literally woke up one morning to see the large weaponry staring down at them, and they knew they were cooked. They left Boston really without even putting up a fight.
Given that this happened in March of 1776, and the United States didn't become the United States for about another four months, the significance of such victories cannot be overstated.
So happy Evacuation Day, everyone. And if you just happen to have a green beer today to celebrate, that's ok, too.