<P> Massachusetts was declared in a state of rebellion in February 1775 and the British garrison received orders to disarm the rebels and arrest their leaders , leading to the Battles of Lexington and Concord on 19 April 1775 . The Patriots laid siege to Boston , expelled royal officials from all the colonies , and took control through the establishment of Provincial Congresses . The Battle of Bunker Hill followed on June 17 , 1775 . It was a British victory -- but at a great cost : about 1,000 British casualties from a garrison of about 6,000 , as compared to 500 American casualties from a much larger force . The Second Continental Congress was divided on the best course of action , but eventually produced the Olive Branch Petition , in which they attempted to come to an accord with King George . The king , however , issued a Proclamation of Rebellion which stated that the states were `` in rebellion '' and the members of Congress were traitors . </P>
when did the revolution begin in the united states
1775