Patriots' Day does not occur on the same calendar date each year. It is a floating holiday, officially observed on the third Monday in April, which causes its specific date to change annually depending on the calendar.
The holiday commemorates the anniversary of the Battles of Lexington and Concord, which took place on April 19, 1775. For many years, it was celebrated on the fixed date of April 19th. However, in 1969, Massachusetts changed its observance to the third Monday in April to create a three-day weekend, a practice followed by Maine. Connecticut officially recognized the holiday in 2018. While the historical event has a fixed anniversary, the official public observance is now tied to a day of the week rather than a specific date.
Due to this "third Monday" rule, the date of Patriots' Day can fall anywhere from April 15th to April 21st. The most famous event held on this day is the Boston Marathon, which has been run on the holiday since 1897. This scheduling firmly ties the modern observance to a specific Monday in April, confirming its variable date on the calendar.
