Battle Description

The Siege of Boston was the first major military campaign of the American Revolutionary War. It began immediately after the Battles of Lexington and Concord, as thousands of colonial militiamen surrounded Boston to prevent British troops from launching further raids into the countryside.

Over the course of nearly eleven months, the Continental Army—under the newly appointed command of General George Washington—fortified positions around the city, including Dorchester Heights. In March 1776, Washington ordered the placement of artillery (transported from Fort Ticonderoga by Henry Knox) on the heights overlooking Boston Harbor. The British, unable to counter the strategic advantage, evacuated the city on March 17, 1776.

Outcome

• Outcome: American strategic victory; British forces evacuated Boston.
• Casualties:
  • American: ~100 killed or wounded (throughout the siege)
  • British: ~300 killed or wounded; ~1,000 Loyalists evacuated with the army

Significance on the Revolution

The successful siege demonstrated the effectiveness of the Continental Army and marked a major morale boost for the Patriot cause. It also secured Boston as a key American stronghold and forced the British to shift their focus to New York. The evacuation of Boston was celebrated throughout the colonies and helped legitimize Washington’s leadership. March 17 is still commemorated in Boston as “Evacuation Day.”