The holiday commemorates the Battles of Lexington and Concord, which were the first armed engagements of the American Revolutionary War on April 19, 1775. Officially established in Massachusetts in 1894, it was created to honor the anniversary of these pivotal events and to replace Fast Day, a previously observed Puritan holiday. The observance is specific to a few states, primarily Massachusetts and Maine, reflecting the regional importance of the historical events.
The historical basis for the day centers on the military expedition by British regulars from Boston to seize a colonial arms cache in Concord. The mission was preceded by the famous "midnight rides" of Paul Revere, William Dawes, and Samuel Prescott to warn colonial minutemen. The first shots were fired at dawn on Lexington Green, followed by a more significant engagement at Concord's North Bridge. The subsequent retreat of British forces back to Boston was marked by continuous guerilla-style attacks from militia along the route, signaling the start of open warfare.
In modern practice, the commemoration blends historical reverence with major civic and cultural events. The most prominent is the Boston Marathon, which has been held on this day since 1897. Historical reenactments of the battles and of Paul Revere's ride are also central to the observance. The holiday was moved from the fixed date of April 19th to the third Monday in April in 1969 to create a three-day weekend, further integrating it into contemporary life while preserving its historical significance.
