Following the confrontations at Lexington and Concord, which ignited the flame of colonial resistance against British rule, the Siege of Boston began as a critical phase in the American Revolutionary War. With tensions escalating after months of political discord and increasingly aggressive measures from British authorities, local militia units rallied in response to the British military. The siege formed around Boston, a strategically vital city for its port and the hub of British operations in New England.

Militias hailing from various colonies, including Massachusetts, Connecticut, New Hampshire, and Rhode Island, assembled and laid siege to the city, effectively surrounding the British troops. The initial impetus came from the desire to respond to perceived injustices, notably the Coercive Acts, which had stoked resentment among the colonists towards British governance. The presence of British soldiers in Boston only intensified these sentiments, leading to increased recruitment and enlistment of volunteers into the militia.

Throughout the siege, which lasted until March 1776, the colonial forces constructed defensive positions and often engaged in skirmishes with British troops. Iconic battles and strategic maneuvers unfolded, setting the stage for future confrontations, notably the Battle of Bunker Hill. The siege not only demonstrated the determination of the colonial populace to resist British authority but also marked the transition from passive resistance to organized military conflict.