A map detailing the tactics used at the Siege of Boston


Siege of Boston

Massachusetts  |  Apr 19, 1775 - Mar 17, 1776

Following the skirmishes at Lexington and Concord in April, 1775 that began the American Revolution, the British Army under military governor Thomas Gage retreated to the safety of Boston. The city was soon surrounded by American militia led by Generals Artemas Ward and Israel Putnam. 

For the next two months, both armies consolidated their forces and constructed defenses. The British launched an assault in June under the direction General William Howe, resulting in the Battle of Bunker Hill. Howe captured the position, however, the heavy casualties impressed upon the British high command the risk of large, direct attacks. 

Appointed by the Continental Congress, Virginian George Washington arrived on July 2 and took command of the American forces. Washington faced the heavy task of molding the various militias into the reconsituted Continental Army. The new commander implemented a new system of uniforms and discipline while at the same time dealing with supply problems as well as the capture of Boston itself.

Washington's line surrounded the city, from Roxbury to Cambridge. Skirmishing between both sides heated shortly after Washington's arrival. Parties of Continentals assailed British outposts on Boston Neck and a raiding party captured the lighthouse on Great Brewster Island. An American force captured and then fortified Ploughed Hill at the end of August. 

Apprised of the situation in North America, the British government issued an order to recall Gage in early August and replace him with Howe. Howe would not assume command until the second week of October but by then the British decided to abandon Boston. The operation would require time and it would take several months to assemble the ships necessary to evacuate the city.

Both sides huddled in their defenses as the New England winter approached. Still, Washington remained focused on taking the city. To that end, he dispatched Boston native Henry Knox to Fort Ticonderoga, to retrieve artillery captured that spring. Knox arrived in early December and began his return trek with fifty-seven guns of various types and calibers in tow. 

The artillery gave Washington a decided advantage over Howe and eliminated the inherent risk involved with a massive assault. On February 16, 1776, Washington called a council of war. At the suggestion of his officers, Washington decided to capture Dorchester Heights, place his artillery on the eminence and render Howe's position untenable. The operation got underway on the night of March 4 and by dawn the Continentals stood ensconced atop the high ground. This success compelled Howe to accelerate his evacuation plans. The last of Howe's army boarded transports and departed on March 17. Within months, Howe would return and face Washington in a campaign for New York.


All battles of the Boston Campaign

Rev War  |  Battle
Lexington and Concord
Massachusetts  |  Apr 19, 1775
Result: American Victory
Est. Casualties: 393
American: 93
British: 300
Rev War  |  Battle
Massachusetts  |  Apr 19, 1775 - Mar 17, 1776
Result: American Victory
Est. Casualties: 98
American: 19
British: 79
Rev War  |  Battle
Bunker Hill
Massachusetts  |  Jun 17, 1775
Result: British Victory
Est. Casualties: 1,532
American: 450
British: 1,054

Related Battles

Massachusetts | April 19, 1775
Result: American Victory
Forces Engaged
Estimated Casualties