The Battles of Lexington and Concord are generally considered the first military engagements of the American Revolutionary War. They took place in Massachusetts on April 19, 1775, when British troops marched from Boston to seize colonial military supplies.
At Lexington, British regulars and Massachusetts militiamen confronted one another, and shots were fired. The British continued to Concord, where colonial forces resisted them. During the retreat to Boston, militia units attacked the British column repeatedly from the surrounding countryside.
The fighting transformed a political crisis into open war. The battles also helped persuade other colonies to support armed resistance and contributed to the creation of the Continental Army. “The shot heard round the world” is a later phrase associated with the opening of the conflict, though the exact identity of the first shooter remains disputed.