Thomas Gage

General Thomas Gage was in charge of the British forces in Boston prior to, and during most of the Siege of Boston. He was replaced by William Howe in October of 1775.

Siege of Boston

April 19, 1775 – March 17, 1776

After Lexington and Concord, colonial militia units from Massachusetts followed British troops back to Boston. In the days that followed, militia from New Hampshire, Connecticut, and Rhode Island joined the Massachusetts militia to help confine British troops to the city. The siege lasted from April 19, 1775, until March 17, 1776. The siege was part of the Boston Campaign and included the Battle of Bunker Hill and the Fortification of Dorchester Heights. It resulted in the British evacuating Boston and Massachusetts.


Prelude to the Siege of Boston

British troops occupied most of Boston and were led by General Thomas Gage, commander-in-chief of the British forces. Gage had also been appointed Governor of Massachusetts by King George III. Gage had four regiments of British regulars under his command in Boston. The British Navy also blockaded the Port of Boston. Around July 1, 1774, Admiral Samuel Graves had arrived at Nantasket Roads, where he took command of the North American Station with orders to enforce the Boston Port Act, blockade Boston Harbor, support the British Army and help Gage enforce the rest of the Coercive Acts.

Battles of Lexington and Concord

On April 19, 1775, Gage sent British troops to Concord with the intent to destroy colonial military stores, and possibly to capture John Hancock and Samuel Adams, who were staying in Lexington with Reverend Jonas Clarke. On the road to Concord, the British Regulars were held up at Lexington by Massachusetts Minutemen who assembled on Lexington Green, under the command of John Parker. It was there, in the early hours of the morning, that the first shots between British regulars and American militia were exchanged, and the American Revolutionary War began.

After the skirmishes in Lexington and Concord, the British marched back to Boston but were followed and harassed the entire way by the militia. When the British reached Boston, many of them camped on Bunker Hill, where they were protected by the guns of the warships sitting in Boston Harbor.

The Siege of Boston Begins

The news that war had broken out, and that the British had attacked quickly spread. The neighboring colonies showed their support by sending troops. Rhode Island sent men under the command of Nathanael Greene. New Hampshire sent theirs under the command of Nathaniel Folsom, but they were actually led by Colonel John Stark. Connecticut also sent men under the command of Major General David Wooster, and two brigadier generals — Israel Putnam and Joseph Spencer.

Map of Boston, 1775

Boston in 1775, during the Siege.

The Massachusetts militia built a siege line around Boston and Charlestown, where the British were garrisoned. The line extended from Chelsea, North of Boston, to Roxbury, South of Boston. On April 22, Gage moved his troops out of Charlestown into Boston, which left Charlestown, Bunker Hill, Breed’s Hill, and Dorchester Heights completely undefended.

The next day, April 23, the Massachusetts Provincial Congress voted in favor of calling more men to arms, and to put the Massachusetts militia under the command of Artemas Ward. The following were also named major generals:

With Boston surrounded by militia from several colonies and the Port blockaded by the British, there were people that wanted out of the town – and others that wanted in. An agreement was reached between Gage the Committee of Safety that opened the roads up, so people could come and go. However, the British were alarmed by the number of people — especially those considered rebels — who were leaving Boston. Gage’s subordinates believed those rebels had value as hostages. Gage reversed course and made it difficult for people to obtain the passes necessary to leave Boston.

At the same time, there were many Loyalists who went into Boston, looking for protection from the British forces. These Loyalists informed Gage of the number of the militia surrounding Boston. Gage decided to remain in a defensive position and awaited the arrival of reinforcements. Gage had fortifications erected at Barton’s Point to the Northwest, Copp’s Hill to the Northeast, and Fort Hill to the East, and South, across the passage to Roxbury. Despite the fortifications, the whole Western side of Boston, along with Boston Common and Beacon Hill, was left open to attack. In order to defend the West, Gage had a small fort erected on Beacon Hill.

Meanwhile, the militia surrounding Boston was trying to find a way to better organize themselves. The largest contingent of troops was the Massachusetts men, under the command of Artemis Ward. Ward’s authority came from the Provincial Congress of Massachusetts, which communicated with Ward through Dr. Joseph Warren, who was the head of the Committee of Safety. The commanders of the other militia groups agreed to submit to Ward as commander-in-chief, however, the chain of communication was lacking.

Although there were small skirmishes throughout the month of May, nothing substantial occurred until May 21. The British were in need of hay to feed their horses, so Gage sent an expedition to Grape Island to retrieve the hay that was needed. The militia responded by sending troops to engage the British. At first, the battle consisted of long-range shooting, but the militia was able to get a sloop from nearby Hingham and get to Grape Island. Once on land, they set fire to the barn where the hay was kept. Roughly 80 tons of hay went up in flames. After this, the militia began removing cattle, sheep, and hay from the islands around Boston.

British Reinforcements Arrive

On May 25, British Generals John Burgoyne, Henry Clinton, and William Howe arrived in Boston aboard the frigate, HMS Cerberus, along with reinforcements. The Cerberus, under the command of Captain John Chads, became the first British warship to arrive in North American.

Battle of Chelsea Creek

More skirmishes broke out on May 27 when Ward sent militia under the command of John Stark and Israel Putnam to capture livestock and seize British supplies on Hog Island and Noddle’s Island in Boston Harbor. A British schooner, HMS Diana, under the command of Lieutenant Thomas Graves, and a sloop opened fire on them. The schooner ran aground and was seized by the militia and burned. The operation was successful, as the militia were able to capture the livestock and provisions.

Gage Offers Pardons to All Rebels Except Hancock and Adams

On June 12, Gage issued a proclamation. The document, written by Burgoyne, offered pardons to all rebels except for Samuel Adams and John Hancock. The proclamation angered the colonists, who were outraged over the British attacks on Lexington and Concord. Now that reinforcements had arrived, Gage began to set a plan in motion to capture Dorchester Heights.

Birth of the United States Army

On June 14, the Second Continental Congress voted on and approved the formation of the Continental Army. This placed all the militia forces outside of Boston under the control of Congress and marked the birth of the United States Army. George Washington was named Commander-in-Chief of the Continental Army on June 15.

Militia Prepare to Seize Bunker Hill

That same day, the Committee of Safety in Boston, having learned of Gage’s plan to seize Dorchester Heights, advised the militia to seize Bunker Hill. Roughly 1,200 men were placed under the command of Colonel William Prescott. The goal of the expedition was to occupy Bunker Hill and to build fortifications, which would overlook both Boston and the Charlestown Peninsula. Prescott and his men assembled on Cambridge Common on the night of April 16. From there, they marched towards Bunker Hill. Upon arrival, however, Prescott and his men chose to build their fortifications on Breed’s Hill, which was smaller than Bunker Hill and closer to Boston.

Battle of Bunker Hill

On June 17, British regulars under the command of Major General William Howe and Brigadier General Robert Pigot landed on the Charlestown Peninsula and marched to Breed’s Hill. As the British advanced, Prescott reportedly told his men, who were low on ammunition, “Don’t fire until you see the whites of their eyes.” When the British were close enough, the militia fired, sending the British into retreat.

The British regrouped and charged again, but were once again forced to retreat. However, when the British charged for the third time, Prescott’s men found themselves out of ammunition and were forced into hand-to-hand combat. The militia was outnumbered and was eventually forced to retreat. However, they had killed more than 200 British troops and wounded roughly 800 more. The American forces lost 100, including Dr. Joseph Warren, and had 300 wounded. Although the American forces lost their strategic position, the Battle of Bunker Hill boosted the morale of the militia, because they proved they could hold their own against the supposedly superior British regulars.

Painting of the death of Joseph Warren by John Trumbull.

Painting of the death of Joseph Warren at the Battle of Bunker Hill by John Trumbull.

Washington Takes Command

Three weeks later, on July 2, Washington arrived in Watertown, Massachusetts. After meeting with the Massachusetts Provincial Congress, he traveled to Cambridge. On July 3, he took command of the Continental Army. Throughout the rest of the summer, Washington worked to organize the various militias into an Army and fortify and expand defenses around Boston.

The British also worked to strengthen their defensive positions in Boston, but General Burgoyne also suggested they use their ships and troops to antagonize the rebels in towns along the southern coast of New England.

Burning of the Guardhouse at Boston Neck and Boston Harbor Lighthouse

Small skirmishes between the Continental Army and British regulars continued throughout the summer.

On July 8, a small force from the Continental Army attacked the British guardhouse at Boston Neck. They routed the British and burned the guardhouse to the ground.

On July 21, an expedition led by Joseph Vose and Benjamin Tupper was sent by Washington to Brewster’s Island, where the lighthouse was located. They set fire to the wooden parts of the lighthouse but were chased off by the British. The damage to the lighthouse was not permanent, and the British were able to make repairs. A second raid on the lighthouse occurred on July 31, under cover of night. They took the British by surprise, overwhelmed them, and set fire to the lighthouse, this time rendering it useless to British ships in the harbor.

Washington grew impatient over the summer and looked for a way to attack the British in Boston. He held a council of war with his generals on September 11 and proposed an attack. His generals were against the idea, and the stalemate continued. A second council was called in October, with the same result.

Howe Replaces Gage

On October 10, William Howe replaced Gage as commander-in-chief of the British forces in North America. Gage returned to England the next day. With Howe in command, there was little change in the British strategy. He continued to strengthen existing defensive positions in Charlestown, on Bunker Hill, and at Boston Neck. He also started building new batteries on Beacon Hill and at Boston Common.

Franklin Meets with Washington

A little more than a week later, on October 18, a committee, sent by the Continental Congress, and led by Benjamin Franklin, met with Washington, his staff, and delegates from Massachusetts, Connecticut, Rhode Island, and New Hampshire. This meeting resulted in the reorganization of the Army, the promise of more troops, and a system for supplying clothing and supplies for the Army. When the committee returned to Philadelphia, the plan was approved by Congress.

Skirmish at Lechmere Point

On November 9, 1775, Howe launched a small offensive, sending an expedition to Lechmere Point to seize cattle. Colonel William Thompson attacked them with his Pennsylvania militia, with support from the Massachusetts militia under the command of Colonel Benjamin Woodbridge and Colonel John Patterson. The British were only able to secure 10 head of cattle before they were driven back.

The Knox Expedition

In an effort to break the stalemate in Boston, he sent Henry Knox to Fort Ticonderoga with orders to retrieve the heavy artillery that has been captured at the forts on Lake Champlain and transport it to Boston. Knox himself had presented the idea to Washington. The Knox Expedition left Boston on November 17 and reached Ticonderoga on December 5. Despite delays due to the winter weather the Expedition successfully moved 60 tons of cannon and other weapons to the camps of the Continental Army outside of Boston, covering approximately 300 miles.

On January 16, 1776, Washington called a council of war and proposed an attack on the British. Washington wanted to attack before more British reinforcements could arrive in the Spring. Less than a week later, the Knox Expedition arrived in Framingham, Massachusetts, East of Boston, on January 25. Knox wrote to Washington, informing him that he had 59 pieces of artillery with him, and all of it was ready to be turned over to the Continental Army. The weapons were moved to Cambridge on January 27. By late February, the artillery, including 35 cannons, had been moved from Cambridge to Roxbury.

Washington tried again on February 16 and 18 to convince his officers to mount an attack on the British. They still disagreed, because they felt that any attack would need to be preceded by artillery bombardment on British defenses, and the Army was short on manpower and gunpowder. Instead of planning an offensive, the council resolved to make preparations to take Dorchester Hill as soon as there was enough firepower. They believed this action would draw the British out of Boston and off of Noodle’s Island, and out into the open.

Fortification of Dorchester Heights

Finally, the Continental Army was ready to make a move. Washington planned to move the artillery to Dorchester Heights, but a distraction was needed.

The Continental Army launched a 3-day bombardment on the British on the morning of March 2, using some of the cannon that had been captured at Fort Ticonderoga and Crown Point. The artillery had been placed at Lechmere’s Point, Cobble Hill in Cambridge, and Lamb’s Dam in Roxbury. The artillery batteries in Cambridge also painted logs to make them look like cannons. This gave the British the impression the Army had more firepower than they really did.

On March 3, troops under the command of General John Thomas quietly marched to Dorchester Heights, muffling the sound of their wagon wheels with straw. They moved the artillery from Ticonderoga, tools, and pre-fabricated fortifications to the top of the hill. By the next morning, they had built the fortifications and had their cannon pointed at the British ships in Boston Harbor.

The British planned an offensive, but two things prevented them from moving ahead. First, Washington learned of the plan and increased the number of troops on Dorchester Heights. Second, a snowstorm hit Boston on March 5.

British Evacuate Boston and Leave Massachusetts

On March 7, Howe decided to evacuate the British troops from Boston. 11,000 British troops were joined by nearly 1,000 Loyalists on the retreat. Although they blew up Castle William in Boston Harbor when they departed, they had agreed not to burn Boston during the retreat, as long as the Americans did not attack. The British contingent marched five miles south of Boston, to Nantucket Roads, where they stayed until March 17.

The British set sail for Halifax, Nova Scotia on March 17, now known as Evacuation Day in Boston.  That same day, Artemas Ward and 500 of his men entered Boston, ending the siege. The next day, General Washington visited Boston, and the main forces of the Continental Army moved into the City on March 20. The British had left 69 cannons behind that the Continental Army was able to salvage and make use of.

Significance of the Siege of Boston

The Siege resulted in the British being driven from Boston, and the colony of Massachusetts, for the rest of the war.

Siege of Boston: In Four Minutes


Citation Information

The following information is provided for citations.

  • Article Title Siege of Boston
  • Coverage April 19, 1775 – March 17, 1776
  • Author
  • Keywords Siege of Boston, Boston Campaign
  • Website Name American History Central
  • Access Date December 5, 2021
  • Publisher R.Squared Communications, LLC
  • Original Published Date
  • Date of Last Update December 1, 2021
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