A bit of a misnomer, the Battle of Bunker Hill took place mostly on Breed's Hill on June 17, 1775. The objective of both the colonists and the British was the larger, adjacent Bunker Hill. The battle took place against the backdrop of the Siege of Boston, marking the beginning of the first major phase of the American Revolution.
The colonists laid siege to Boston in an effort to contain the British base of operations. Having received reinforcements during the first three months of the siege British generals William Howe, John Burgoyne and Henry Clinton decided to seize the unoccupied hills near Boston as the first step to breaking out. Learning about the plan, 1200 colonists under William Prescott moved onto Breed's Hill and hastily prepared fortifications. The redoubt on the southern end was composed of six-foot earthen walls with wood planks for men to stand on and shoot.
3800 British troops were sent to dislodge the colonists. The first assault, launched around 3 p.m., was promptly repulsed. With reinforcements streaming in by boat, the British made a second, determined assault that was also repulsed. The third British assault proved successful as the colonists ran out of ammunition. The British, armed with bayonets, gained the advantage in hand-to-hand combat as the colonists had no bayonets. Israel Putnam's attempt to establish a new line on Bunker Hill failed but most of the colonial troops escaped before the British could surround them.
Despite driving the colonists from Bunker Hill, the battle was costly for the British, with over 1000 casualties compared to only 450 colonial. The battle proved that colonists were determined enough to stand up to British regulars.
The siege ultimately proved effective. Eleven months after the siege began, while under pressure from American troops under George Washington, the British finally withdrew.