Gaspard-Joseph Chaussegros de Léry (July 20, 1721 – December 11, 1797), his first name was also sometimes written Joseph-Gaspard. He was a military engineer and a political figure in Lower Canada. During the Seven Years' War he proved himself to be an outstanding officer and was one of only a few colonial officers held in high esteem by the Marquis de Montcalm. In recognition of his military service, in 1759 he was made a Chevalier of the Order of Saint Louis. n 1763, after the British Conquest of New France, he and his wife, Louise Martel de Brouage, were the first French Canadian couple to be presented to the English Court, drawing the compliment from King George III that if all Canadian ladies resembled Mme de Léry then he had "indeed made a conquest".
Born at Quebec City in 1721, he was the son of Gaspard-Joseph Chaussegros de Léry and his wife Marie-Renée, daughter of Captain René Legardeur de Beauvais (1660–1742), holder of the Grand Cross of the Order of Saint-Louis.
He joined the colonial army in 1733 and became an assistant engineer in 1739. Chaussegros de Léry took part in raids against the British in New England, helped maintain French fortifications in New France and was in charge of the construction of Fort Saint-Jean. In 1753, he married Louise, the daughter of François Martel de Brouague, commandant of the Coast of Labrador. He took part in Louis-Joseph de Montcalm's capture of Fort Oswego in 1756 and, in 1757, was promoted to captain for his success at the Battle of Fort Bull. He was wounded at the Battle of the Plains of Abraham and sent back to France in 1761. He had become the seigneur of Léry after his father's death.
At some point, Chaussegros de Léry produced a finished copy of a map of the west. The original work had been done by Christopher Dufrost de La Jemeraye, a nephew of Pierre Gaultier de Varennes et de La Vérendrye.
Chaussegros de Léry was not given any opportunities by the French and returned to Quebec by way of England in 1764. He was named chief road commissioner by Governor Guy Carleton in 1768 and served on the Legislative Council and Executive Council of Quebec. In 1792, he was named to the Legislative Council of Lower Canada. He sold the seigneury of Léry in 1766 but later acquired the seigneuries of Perthuis, Rigaud-Vaudreuil, Gentilly, Le Gardeur and Sainte-Barbe.
He died at Quebec in 1797.
- A Fort Saint-Jean plaque erected by Historic Sites and Monuments Board of Canada in 1926 at the Royal Military College Saint-Jean mentions de Léry. "Constructed in 1748 by M. de Léry under orders from Governor la Galissonnière. For a long time this post was a rendezvous for all the military expeditions towards Lake Champlain..."
- The DeLery Building at the Royal Military College Saint-Jean was named in his honour.
- The portage across Marblehead Peninsula is named DeLery Portage because of his documentation of it in his 1754 journal.