The core component of the search query is the term "Patriots' Day," which functions as a proper noun. A proper noun is the specific name of a person, place, or entity, and in this context, it refers to a statutory public holiday. Patriots' Day is officially observed in Massachusetts on the third Monday of April each year. In the current year, 2024, this date is Monday, April 15.
The holiday commemorates the anniversary of the Battles of Lexington and Concord, the initial armed engagements of the American Revolutionary War on April 19, 1775. While originally celebrated on the fixed date of April 19, the Commonwealth of Massachusetts enacted legislation in 1969 to move the observance to the third Monday of the month. This change aligned the holiday with the federal Uniform Monday Holiday Act, designed to create more three-day weekends for the nation's workers.
The practical application of this floating date is most prominently seen in the scheduling of the Boston Marathon. Since its inception in 1897, the marathon has been traditionally held on Patriots' Day. Therefore, the determination of the third Monday in April is a critical logistical factor not only for state and municipal government operations but also for this major international sporting event and the associated public school vacations throughout the state.