François Joseph le Mercier (4 October 1604 – 12 June 1690) was a prominent French Jesuit in the early missions to New France and the Huron people.
He joined the Society of Jesus at Paris on 22 October 1622[1] and completed fifteen years of study and teaching before being sent on mission to Canada.
The settlement at Ihonatiria was ravaged by smallpox which greatly reduced the population, so the mission was abandoned in 1637 and relocated to the Huron capital Ossossané (now in Simcoe County, Ontario).
Not willing to expose others to dangers perils he was not ready to face, he appointed Jérôme Lalemant vice-superior, while Le Mercier led a missionary expedition to the Onondagas.
[1] Le Mercier was recalled to France in 1673 and made "Visitor of the French missions in South America and in the Antilles".
[1] The Jesuits in North America in the Seventeenth Century, by Francis Parkman is sourced largely from the Relations written by Le Mercier.