Patriots' Day is HAI CommunityMonday meaning some Americans will mark the beginning of the nation's war for independence.

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.

Patriots' Day was first celebrated in Massachusetts in 1894 and was proclaimed by then-governor Frederic Greenhalge to diffuse a budding rivalry between 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 that started the American Revolution.

The state holiday can affect the availability of services in the states that celebrate.

Here's what is open and closed on Patriots' Day.

What is open on Patriots' Day?

Since the holiday is not a Federal one, Federal offices — including the Post Office — will be open.

Banks may be open as well as retail stores. Target and Walmart will be open.

The MBTA will run on its standard weekday schedule.

What is closed on Patriots' Day?

State, county and municipal offices in the states that celebrate are closed on Patriots' Day. Schools will be closed as well as libraries.

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. The professional men start at 9:37 a.m. ET and the professional women starting at 9:47 a.m. ET.

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.

Is Patriots' Day celebrated outside of New England?

Patriots' Day is a school holiday in Wisconsin. Schools in the state will be closed.

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.