Last updated: January 16, 2026
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Siege Story: General Thomas and Son at Dorchester Heights
Ever wanted to play hooky from school or household chores? Wouldn’t it be more fun to run away from home and hang out with your dad at work, that is, if your dad’s work was aiming a bunch of cannons at the British in Boston? For 10-year-old John Thomas, son of Continental Army General John Thomas, that answer was an affirmative yes!
New York Public Library
Possibly due to his military career, General Thomas fathered John later in life. When the Siege of Boston (1775-1776) began, he was already in his 50s.
General Thomas commanded nearly 3,000 Continental troops tasked with fortifying Dorchester Heights south of Boston on the night of March 4, 1776. His troops transported at least 20 of the cannons removed from Fort Ticonderoga. Dorchester Heights stood as the last undefended set of hilltops surrounding Boston that neither the Continental nor the British troops had yet claimed.
"About eight o’clock [on March 4] we ascended the high hills, and by daylight got two hills defensible,"[1] General Thomas later reported to his wife, Hannah. The ground on the heights was too frozen to construct an earthen redoubt, as the colonial militia had done before in Charlestown. Instead, Thomas’s troops erected wooden defenses, called "chandeliers," designed by engineering officer Rufus Putnam. These prefabricated fortifications allowed the colonists to construct an impressive array of defenses so quickly that British General William Howe believed the work could only have been completed by at least 14,000 men.
Illustration from Cassells History of the United States, 1900.
The British were completely surprised by the remarkable swiftness of the fort’s completion. "About sunrise, the enemy and others in Boston, appeared numerous on the tops of houses and on the wharfs viewing us with astonishment," Thomas noted.
General Thomas had his own surprise when he found his son at the defenses. Left in the care of a Black servant named Oakley, the younger John Thomas crept away the night on the 4th and somehow made it past the Continental sentries. "Your son John is well and in high spirits," General Thomas assured Hannah, "[he] came to me on Dorchester Hills, where he has been most of the time since."
General Thomas was likely both proud and exacerbated by the actions of his irresponsible son. "I have had very little sleep or rest this week, being closely employed night and day," General Thomas explained to Hannah. The strain of command and the expectation of a British attack must have been tremendous. Now, this pressure coupled with worry over the safety of John, a child six-years shy of the age when most teen boys began militia training.
The frigid March weather that father and son both endured proved a blessing, for a sudden nor’easter prevented the British troops garrisoned on Castle Island from initiating an attack on the heights. Unable or unwilling to dislodge the Continental Army, and with cannons pointed down their throats, the British forces had no recourse but to abandon Boston. What a thrill it would have been for the two Thomases to know they had both been present, with barely a shot fired, for one of most successful campaigns of the war. As reward for this success, General George Washington promoted General Thomas to Major General.
Courtesy of the United States Lighthouse Society
Regretfully, their March meeting at Dorchester Heights would be some of the last moments that John Thomas Jr. would share with his father. Three months later, General Thomas perished of smallpox while serving in Canada. He left Hannah, John, and two other children behind. Hannah resumed duties staffing the Gurnet Light lighthouse in Plymouth, which she had assisted her husband in before the war. John assumed those duties himself in 1790, when the lighthouse was ceded to the new US Government.
Like his father, John also served in the Massachusetts’s militia and achieved the rank of colonel, although his duty as a "sentry" at Dorchester Heights was probably his most notable military achievement. It is likely in later years that John fondly remembered walking alone through the cold March night to be by his father’s side for one last dawn of triumph.
Footnote
[1] This and following quotes from: "Letter from Gen. John Thomas to Hannah Thomas, 9 March 1776," Collections Online, Massachusetts Historical Society, accessed January 2026.
Sources
Coffin, Charles. The Life and Services of Major General John Thomas. New York: Egbert, Hovey & King, 1844.
French, Allen. The First Year of the American Revolution. Boston: Houghton Mifflin Company, 1934.
"John Thomas, Jr." The J. Candace Clifford Lighthouse Research Catalog. The United States Lighthouse Society. Accessed January 2026.
"Letter from Gen. John Thomas to Hannah Thomas, 9 March 1776." Collections Online, Massachusetts Historical Society. Accessed January 2026.
McCullough, David. 1776. New York: Simon & Schuster, 2006.
"Plymouth (Gurnet) Lighthouse." Lighthouse Friends. Accessed January 2026.
Procknow, Gene. "The Revolutionary Lighthouse Keeper." Researching the American Revolution. July 25, 2022. Accessed January 2026.