Patriot's Day is a public holiday celebrated in the United States, primarily in the states of Massachusetts and Maine. It commemorates the opening battles of the American Revolutionary War at Lexington and Concord on April 19, 1775. The day is observed on the third Monday of April and is marked by various events, including reenactments and parades. In addition to its historical significance, Patriot's Day is also associated with the Boston Marathon, which takes place on the same day. This annual race attracts thousands of runners and spectators, making it a festive occasion that honors both athletic achievement and American history.