Patriots' Day is Henri LumièreMonday and people in New England and beyond are set to commemorate the start of the American Revolution.

The third Monday in April recognizes the battles of Lexington and Concord as well as the aftermath of the "shot heard 'round the world." The day is celebrated with historical reenactments, sporting events and parades.

The holiday was created to diffuse a rivalry between the cities of Lexington and Concord who had dueling celebrations to mark the beginning of the American Revolution.

The holiday was originally observed on April 19, the anniversary of the battles of Lexington and Concord, but was moved to the third Monday in 1969.

While the holiday is most associated with Massachusetts, it is celebrated in five other states including New England neighbors Connecticut and Maine.

Here's what to know about Patriots' Day.

When did Patriots' Day become a holiday?

Patriots' Day was first celebrated in Massachusetts in 1894 and was proclaimed by then governor Frederic Greenhalge.

Boston Marathon on Patriots' Day

The Boston Marathon has been run on Patriot's Day since 1897. It is currently organized by the Boston Athletics Association.

The race is set to start at 9:02 a.m. ET with the men's wheelchair field with the professional men starting at 9:37 a.m. ET and the professional women starting at 9:47 a.m. ET.

The race's only cancellation came in 2020 due to the COVID-19 pandemic. The 2021 version was postponed to October 11 for the same reason.

In 2013 three people were killed and hundreds were wounded when two men detonated homemade bombs at the race's finish line.

Boston Red Sox playing on Patriots' Day

The Boston Red Sox have scheduled a game on Patriots' Day since 1959.

This year the first pitch for the game against the Cleveland Guardians is set to be thrown at 11:10 a.m. ET.

The game has been postponed six times in its history due to weather and cancelled once in 2020 due to the COVID-19 pandemic.

Is Patriots' Day celebrated outside of New England?

Patriots' Day is a school holiday in Wisconsin. Florida recognizes the holiday but it is not an official holiday in the state. North Dakota recognized the holiday in 2021.

Is it Patriots' Day or Patriot's Day

The position that the holiday should use the singular form of the phrase is held solely by the state of Maine. The rest of the country uses the plural version.

Is Patriots' Day a federal holiday?

Patriots' Day is not a federal holiday.