Last updated: January 27, 2026
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"Bring on a Rumpus:" The Seizure of Dorchester Heights
Boston Public Library
A high-flying gull looking down over Boston and its environs in the late winter of 1776 would have seen a landscape, from Cambridge to Roxbury, riddled with forts, redoubts, gun batteries, and entrenchments. Colonial troops had fortified virtually the entire area north and south of the Charles River. In what is now Somerville and Cambridge, colonists erected defenses on Winter Hill, Prospect Hill, Plowed Hill, Butler Hill, and Lechmere Point. Near Roxbury, colonists held the heights in places known as the Lamb’s Den, Fort Hill, and Brooklin Fort. The area’s geography, comprised of hills and the narrow Mishawum and Shawmut peninsulas (Charlestown and Boston respectively), put Boston’s British occupiers at a military disadvantage, unable to penetrate the Massachusetts mainland.
Of all the areas fortified there was one notable exception: the yet unclaimed and undefended Dorchester Heights. In the chess game for military dominance of Boston the only move yet to be played was for control of these hills. Although unbeknownst at the time, control of these high points would have an outsized influence in the cause of independence.
Breaking the Siege
British troops planned on seizing Dorchester Heights as early as June 18, 1775, using the heights as a base to drive colonial forces out of Roxbury. However, colonial fortification of Charlestown, and the following Battle of Bunker Hill on June 17, diverted the British strategy for breaking the siege. As a result, Dorchester Heights remained no-man’s land for the rest of 1775. Inexplicably, British troops did land on Dorchester on January 14, 1776, burned a few abandoned buildings, and then departed. This was likely in response to colonists burning the ruins of Charlestown a week before. However, the British command seemed oblivious to the potential threat posed by hostile forces seizing the heights. According to Loyalist Justice Peter Oliver, "the general answers were that there was no danger from it, and that it was to be wished that the rebels would take possession of it, as they could be dislodged."[1]
General George Washington’s Continental Army, despite being critically low on gunpowder, did not remain idle during the siege’s long winter. Shortly after the British raid on Dorchester, Colonel Henry Knox arrived in Cambridge on January 27. He had been on the move for the previous 52 days, transporting 59 cannon barrels by ship and horse-drawn sledge from Fort Ticonderoga in New York to Massachusetts. The newly emboldened Continental Army now had the heavy artillery they had previously lacked at the Battle of Bunker Hill.
National Archives
Seizing the Heights
After subordinate officers overruled a direct attack across the ice of the frozen Charles River, Washington decided the time was finally right to "bring on a rumpus."[2] On March 2, artillery opened fire on Boston from Cambridge. One of the mortars brought from Ticonderoga burst apart as it lobbed explosive shells. The British fired back, and the cannon exchange lasted on and off for the next several days but did not result in significant damage or casualties to either side.
The firing from Cambridge served as a diversion for the Continental Army’s true plan. On March 4, General John Thomas led an estimated 3,000 troops from Roxbury to the summit of Dorchester Heights, an area known as the twin hills, each approximately 118 feet above sea level. Thomas also brought about 20 of the Ticonderoga cannons. Constructing a redoubt on the heights was impossible, the ground simply too hard and frozen. Anticipating this, Rufus Putnam (cousin to General Israel Putnam) designed portable prefabricated fortifications, including chandeliers (wooden frames) and fascines (bundles of woody material). Transporting this fort-on-the-go required 800 oxen and 360 carts. Soldiers used hay bales to muffle the sound of the grinding wheels.
As soldiers worked throughout the night assembling this fort on Dorchester Heights, Washington reminded the troops, "Remember, it is the fifth of March, a day ever to be forgotten; avenge the death of your brethren," as a reference to the anniversary of the 1770 Boston Massacre.[3]
Daylight soon revealed to the British that again they had been caught napping while a fort had been built nearly atop of them. "My God, these fellows have done more work in one night than my army could do in three months,"[4] groused General William Howe, the British Commander-in-Chief. Although averse to attacking another well-fortified area head-on, Howe and the British Army could not ignore the threat posed by the cannons on Dorchester Heights.
National Park Service/©Louis S. Glanzman
A direct attack from Boston was impossible because of a massive tidal flat north of the Dorchester peninsula. Instead, the British planned to ferry troops from Boston’s Long Wharf to their garrison at Castle William, located offshore on nearby Castle Island. From there, the channel from Castle Island to Dorchester would be crossed and the colonial defenses assaulted on their eastern flank. Washington, meanwhile, prepared to invade Boston with 4,000 reserve troops across the Charles River should the British move against Dorchester.
However, the "rumpus" proved an anticlimax. A violent March nor’easter scuttled the British’s naval designs for getting men from Boston to Castle Island. For the American soldiers on Dorchester Heights, the change in weather meant enduring almost intolerable cold with practically no shelter. By March 6, Howe made the fateful decision to abandon Boston, a move that shocked Loyalists still taking refuge in the town. Dueling cannon blasts continued, nonetheless. In an exceptionally violent exchange, the British fired repeatedly at Foster’s Hill in Dorchester, in one instance killing four Americans with a single shot. After the firing subsided, a total of 700 cannon balls were collected from the impacted earth of Dorchester. After this furious but futile display of firepower, Howe prepared for the inevitable evacuation of Boston.
Engraving published in "The Illustrated Life of George Washington" written by T. Headley, New York, G. &. F. Bill, 1859.
Forcing the Evacuation
On March 17, 1776, 11,000 people, including soldiers, Loyalists, women, and children boarded 120 ships in Boston Harbor. General Artemis Ward, second in command to Washington, led the Continental Army into the newly freed town. They were impressed by the thoroughness of the British defenses: "…Boston was almost impregnable, every avenue fortified."[5] In their haste the British had left behind cannons and 30,000 pounds sterling of material, from blankets to spiked cannons. Three days later an explosion wracked Castle Island as British engineer John Montressor (who had organized the first British defenses in Charlestown) directed the demolition of Castle William. Eventually, by March 27, the weather was favorable to the dispirited British fleet, and apart from some outliers in the outer part of Boston Harbor, the fleet departed for Halifax, Nova Scotia, never to return in force.
The victory of Dorchester Heights was one of the most pivotal events of the Revolutionary War. From the bloody defeat at Bunker Hill, to the nearly bloodless victory at Dorchester, the evolving Continental Army proved itself equal to the might of Britian. Victory in Boston was made possible by the planning and leadership of Washington, Knox, Thomas, and countless others. Their bold, decisive action in March 1776 pushed Congress to be equally bold four months later by adopting a Declaration of Independence. Success in ending the Siege of Boston transformed independence from a distant hope into an achievable goal, shifting the conflict from a local military struggle to a continent-wide fight for liberty and self-determination.
Footnotes:
[1] John Rhodehamel, ed., The American Revolution: Writings from the War of Independence (New York: Library of America, 2001).
[2] "George Washington to Burwell Bassett, 28 February 1776," Founders Online, National Archives. [Original source: The Papers of George Washington, Revolutionary War Series, vol. 3, 1 January 1776 – 31 March 1776, ed. Philander D. Chase. Charlottesville: University Press of Virginia, 1988, pp. 386–387.]
[3] Arthur Gilman and Dorothy Dudley, TheatrumMajorum: The Cambridge of 1776: Wherein is Set Forth an Account of the Town, and of the Events it Witnessed (Cambridge, MA: Lockwood, Brooks, & Co., 1876).
[4] Allen French, The First Years of the American Revolution (Boston: Houghton Mifflin, 1934).
[5] "George Washington to Lieutenant Colonel Joseph Reed, 19 March 1776," Founders Online, National Archives. [Original source: The Papers of George Washington, Revolutionary War Series, vol. 3, 1 January 1776 – 31 March 1776, ed. Philander D. Chase. Charlottesville: University Press of Virginia, 1988, pp. 493–494.]
Sources
Founders Online, National Archives.
McCullough, David. 1776. New York: Simon & Schuster, 2006.
Zielinski, Adam. "Sir William Howe: The Man Who Could Not Quell a Rebellion." The American Battlefield Trust, 18 March 2020. Accessed January 2026.