NPS Graphic. Map courtesy of Boston Public Library. From April 1775 to March 1776, Boston took center stage in a developing war between colonial and British forces. For eleven months, colonial troops laid siege to British-occupied Boston in what became known as the Siege of Boston. The battlefield extended throughout Boston Harbor and the hilly coastline. The siege included flashpoints, such as the Battle of Bunker Hill, as well as numerous skirmishes around greater Boston and on the Boston Harbor Islands. It took a strategic move by George Washington to fortify Dorchester Heights in South Boston to force the evacuation of the British from Boston on March 17, 1776. Boston became the first town to taste American liberty, months before the Declaration of Independence. Explore the content below to learn more about key moments and stories of the Siege of Boston. 
The British Evacuation of Boston
With the rapid completion of American fortifications at Dorchester Heights, the British decided to evacuate from Boston on March 17, 1776. 
Post Siege: Harbor Happenings
After evacuating Boston, a few British ships remained in the outer harbor, causing continued tension between Americans and the British. 
The French in Boston
During the American Revolutionary War, Boston proved integral to the relationship between the French and American colonists. 
Interactive Map: The Siege of Boston
Explore the extent of the Siege of Boston of 1775-1776 with this interactive map depicting fortifications and troop locations. Stories of the Siege |
Last updated: February 23, 2026