The Battle of Lexington and Concord took form before dawn on April 19, 1775. Having received word that the regular army had left Boston in force to seize and destroy military supplies in Concord, several dozen militiamen gathered on the town common, and then eventually went to the tavern to await the arrival of the British troops.

Definite word reached them just before sunrise, and Captain Parker'scompany of militia left the tavern to assemble in two ranks on the common. Following the arrival of the army, a single shot was fired; by whom, it is still unknown. With this shot, the American Revolutionary War began.

Although best known as the headquarters of the militia, Buckman Tavern is also noteworthy as perhaps the busiest of Lexington's 18th-century taverns. It housed the first village store in Lexington, and later, in 1813, the first town post office.