Louis Jolliet (French pronunciation: [lwi ʒɔljɛ]; September 21, 1645 – after May 1700) was a French-Canadian explorer known for his discoveries in North America.

[1] In 1673, Jolliet and Jacques Marquette, a Jesuit Catholic priest and missionary, were the first non-Natives to explore and map the Upper Mississippi River.

[3] Jolliet's stepfather owned land on the Ile d'Orleans, an island in the Saint Lawrence River in Quebec that was home to First Nations.

Jolliet spent much time on Ile d'Orleans, so he likely began speaking Indigenous languages of the Americas at a young age.

Jolliet entered a Jesuit school in Quebec as a child and focused on philosophical and religious studies, aiming for the priesthood.

[4] While Hernando de Soto was the first European to make official note of the Mississippi River by discovering its southern entrance in 1541, Jolliet and Marquette were the first to locate its upper reaches, and travel most of its length, about 130 years later.

Europeans eventually built a trading post at that shortest convenient portage between the Great Lakes and Mississippi River basins.

Father Marquette stayed at the mission of St. Francis Xavier at the southern end of Green Bay, which they reached in August.

Like Jolliet, she was Canadian born, a daughter of Francois Byssot de la Riviere and his wife Marie Couillard.

There is no listing of his death or burial place, and the sole record of his fate is the notation that a mass for his soul was said in Quebec on September 15, 1700.