The first shots of the American War of Independence were fired at Lexington on April 19th, 1775. British General Thomas Gage, the military governor of Massachusetts, had received intelligence that colonial militia were storing weapons and ammunition in the town of Concord. He therefore dispatched around 700 British regulars from Boston under Lieutenant Colonel Francis Smith, with orders to march to Concord, seize the military supplies and arrest the colonial leaders Samuel Adams and John Hancock, who were believed to be nearby.
The Americans had been warned that the British were coming. Paul Revere and William Dawes rode through the countryside during the night, alerting local militia companies and warning that British troops were advancing. By the time the British reached Lexington at dawn, around 70 colonial militiamen had gathered on the village green under Captain John Parker. They were vastly outnumbered and Parker ordered his men not to fire unless the British did so first. The two sides faced one another in the darkness and confusion before a shot rang out. Nobody knows for certain who fired it. The British then opened fire, killing eight Americans and wounding several more before continuing towards Concord.
The British reached Concord and began searching for the colonial weapons, but much of the military equipment had already been moved or hidden by the local militia. Meanwhile, hundreds of armed colonists were gathering in the surrounding countryside. At the North Bridge outside Concord, colonial militia confronted a detachment of British soldiers guarding the crossing. This time, the Americans advanced, and fighting broke out. The British were forced to withdraw back towards Concord, having failed to destroy most of the supplies they had been sent to seize.
The British column now faced a much more dangerous journey. What had begun as a disciplined military expedition was turning into a retreat through hostile territory. Thousands of colonial militiamen had mobilised across the countryside, many of them experienced hunters and veterans of earlier conflicts despite having little formal military training. They used the landscape to their advantage, firing from behind walls, trees and buildings before withdrawing and attacking again further along the road. The British regulars, exhausted after hours of marching and fighting, were increasingly surrounded.
The situation became critical when British reinforcements under General Hugh Percy arrived from Boston. The fresh troops prevented the retreat from becoming a complete disaster and used artillery and disciplined formations to drive the militia away from the road. Even so, the British suffered heavy casualties as they fought their way back towards Boston. By the time they reached the city, more than 250 British soldiers had been killed, wounded or captured, compared with roughly 90 American casualties.
Militarily, the British had survived the expedition and returned to Boston, but strategically they had failed almost every objective they had been given. They had not captured Adams or Hancock, had failed to destroy the majority of the colonial weapons and had suffered significant casualties against a force they had expected to disperse easily. Worse still, thousands of colonial militia now surrounded Boston, trapping the British army inside the city.
What had begun as an attempt to enforce British authority in Massachusetts had therefore produced the opposite result. The fighting at Lexington and Concord transformed years of political tension into open warfare. Within weeks, thousands of Americans would gather around Boston, and the conflict that had begun with a single unexplained shot would develop into a full-scale war for American independence.