The battles of Lexington and concord , fought on April 19, 1775, kicked off the revolutionary war (1775- 83) . Tensions had been building for many years between residents of the 13 American colonies and the British authorities, particularly in Massachusetts. On The night of April 18, 1775, hundreds of British troops marched from Boston to nearby concord in order to seize an arms cache. Paul revere and other riders sounded the alarm, an colonial militiamen began mobilizing to intercept the redcoat column. A confrontation on the Lexington town green started Off the fighting, and soon the British were hastily retreating under intense fire. Many more battles followed, and in 1783 the colonists formally won their independence.