After retreating from Lexington in April, 1775, the British Army occupied Boston for several months. Realizing the need to strengthen their position in the face of increasing anti-British sentiment in and around Boston, plans were developed to seize and fortify nearby Dorchester Heights and Charlestown peninsulas. The peninsulas offered a commanding view of the seaport and harbor, and were important to preserving the security of Boston. The Americans caught word of the British plan, and decided to get to the Charlestown peninsula first, fortify it, and present sufficient threat to cause the British to leave Boston. On June 16, 1775, under the leadership of Colonels Putnam, and Prescott, the Patriots stole out onto the Charlestown Peninsula with instructions to establish defensive positions on Bunker's Hill. For reasons that are unclear, they constructed a redoubt on nearby Breed's Hill, where most of the battle took place. The next morning (June 17, 1775), the British were astonished to see the rebel fortifications upon the hill and set out to reclaim the peninsula.

General Howe served as the commander of the British main assault force and led two costly and ineffective charges against the Patriot's fortifications without inflicting significant casualties on his opponents. After obtaining 400 reinforcements which included sorely needed ammunition for his artillery, Howe ordered a bayonet charge to seize Breed's Hill. In this third attempt, the British were finally able to breach the breastworks of the American redoubt and the Patriots were forced to retreat back to the mainland.

This battle, though victorious, proved costly for the British. Of the 2400 British soldiers in Howe's command, the 1054 casualties accounted for nearly forty percent of their ranks. The American casualties were 441, including 30 captured, with most being inflicted during the retreat. The battle served to proved to the American people that the British Army was not invinsible. It became a symbol of national pride and a rally point of resistance against British rule.