General Thomas Gage, the military governor of Massachusetts, knew he was sitting on a powder keg.  Since Parliament had imposed the Coercive Acts in response to the Boston Tea Party, American hostility toward British policies had increased and civil disobedience had spread.  Believing that he must take aggressive steps to prevent an escalation of the conflict, he resolved to seize the arms and ammunition stockpiled by the local militias in Concord and Worcester. ¹⁸⁸

Gage took huge precautions to keep his plan secret. But nothing could be kept secret in Boston in 1775.  Anti-British Patriots like Paul Revere kept a close watch on every move made by the British troops occupying Boston. Informers filled in the details.  By the time Gage was ready to act, only the exact route was still unknown.  But even that was ascertained before the troops began piling into the small boats that would carry them across the Back Bay to Charlestown for their march to Concord.

Paul Revere’s midnight ride, therefore, brought news to Patriot militia that were already on hyper-alert.  As 700 British troops waded from their boats to the shore, and then set off with wet feet toward Concord, bells and musket shots rang through the night warning colonists and rattling the soldiers who knew how combative the Americans could be.  

Therefore, it was probably inevitable that someone would panic or overreact. When the British troops reached Lexington around dawn—half way to Concord—they were surprised to find a band of American militia standing on the green to the side of the road. The men had gathered hours earlier—by this time half had returned home.  But those remaining stood in silence to protest the assertion of British power represented by the troops passing through their village.

The Redcoats could have ignored them.  The militiamen were not blocking the road.  On another day they just might have. But perhaps because they were wet and cold; perhaps because they had been unnerved by all the bells and guns shots that echoed through the night, the British soldiers enthusiastically formed ranks when their commander, Major Pitcairn,ordered them into battle formation.  When Pitcairn ordered the “damned rebels” to lay down their arms, his men shouted their approval. When someone fired a shot—to this day no one knows who—the soldiers jumped at the chance to deliver a volley.

A few Americans returned the fire.  But clearly the militia got the worst of the exchange.  Eight were killed and ten were wounded; only one British soldier received a minor wound. But the British officers were more embarrassed by their loss of control than celebratory.  They quickly re-formed ranks and set off for Concord. 

The rest of the march was accompanied by even more warning shots.  By the time the British reached Concord, the town’s militia had been augmented by units from neighboring villages.  Yet initially, they offered no resistance to the British troops marching through the center of town.  Their destination was James Barrett’s house, on the other side of the North Bridge about a half mile from the center of the village.  It was believed that the munitions were stored there.  Three companies were sent across the bridge and up the small hill to Barrett’s house while three other companies remained at the bridge and kept a wary eye on the swelling militia watching from a nearby rise.  

The morning may have passed without further event.  The companies searching Barrett’s house found nothing of significance.  The British officers were anxious to get back to Boston without further event. But then a fire broke out downtown.  How it started no one is sure but the militia quickly concluded that the rest of the British force, still in town searching buildings, was torching their village.  As a result, they ran to the bridge and opened fire on the Redcoats barring their crossing.  The skirmish lasted only a few minutes, killing two Americans and three British. The rest of the British soldiers raced back into town, rejoined the rest of their force, and began the long march back to Boston.

Disorganized, shocked by the exchange, and tending to their wounded, the American militia did not immediately follow the British troops.  But they were not too far behind.  At Meriam’s corner, about one mile east of Concord, the militia caught the British and mounted the first of the guerrilla attacks that would turn the Redcoats’ sixteen mile trip back to Boston into a nightmare.  Shooting from behind rocks and trees, the Americans took a brutal toll on the retreating troops.  

British officers did what they could to guard their slow-moving column. They sent out flankers to roust the ambushers; the fighting between these and the militia was particularly brutal, often hand-to-hand.  In several places, the flankers managed to trap their American assailants between them and the British column where they became sitting ducks.  At Lexington, moreover, the retreating British column ran into a 1200 British troops sent out to re-enforce them.  But by mid-afternoon, just about time the British re-enforcements arrived, another batch of militia from more distant villages began to pour in.  Some of the most intense fighting occurred after these fresh bodies joined the pursuing force.  

Even with enforcements, there would be no safety or rest for the British until they reached Charlestown around dusk.  By the time they reached their quarters in Boston, they had lost 273 men—73 killed, 174 wounded, and 26 missing.