Captain John Montresor (22 April 1736 – June 1799) was a British Army officer and cartographer who served in North America during the American War of Independence.

In 1754, he accompanied his father to America and served as an ensign in the 48th Regiment of Foot on the expedition to Fort Duquesne, also performing as a supernumerary engineer.

With the defeat of the French, Montresor was sent to neighbouring villages and as far afield as Cape Breton, using the language of his Huguenot ancestors to elicit oaths of allegiance.

He was also twice sent overland from Quebec to Boston with dispatches, on one of these journeys, in a mid-winter blizzard, being reduced to eating belt and shoe leather in order to avoid starvation.

It is said that he kindly sheltered Hale in his office, giving him pen and paper to write final letters to his family, and that the execution moved him deeply.

He also participated at Brandywine later that year, and accompanied the army to Philadelphia where he launched the attack that destroyed his own Mud Island defences.

Again superseded in his role as chief engineer, he returned to England and in March 1779 resigned from the army, bringing to an end over two decades of American service, all reported in journals (although many of these were lost).

In England, he was called before Parliament to testify on the conduct of the war and on several occasions was required to support his expenditures during his various campaigns (for which he is said to have been imprisoned at one point).

After Frances's mother died, she was adopted by her maternal aunt, Margaret, and her husband, Crean Brush, one-time secretary of the Assembly of the Colony of New York.

As to her paternity, when her daughter Frances "Fanny" Allen entered Hôtel-Dieu in 1808, her mother's maiden name was recorded as Montresor.

Her tombstone names her Montezuma, while an 1858 history written using family information calls her Frances Montuzan, relating that her father was a British colonel killed in the French and Indian War.