Louis Jolliet, also known as Louis Joliet (September 21, 1645 – May 22 1700), was a Canadian explorer born in Quebec City. Jolliet is important for his discoveries in North America. Jolliet and missionary Father Jacques Marquette, a Catholic priest, were the first white men to explore and map the Mississippi River.

The son of a wainwright, Louis Jolliet was born in Quebec City, Canada, on September 21, 1645. He gave great promise of scholarship, especially in the mathematics, in the Jesuits' school at Quebec, and received minor orders in 1663. He was talented in music, playing the flute, trumpet, and harpsichord. He loved drawing and creating maps. This sparked his first interests in exploring. In 1671, he is seen standing by the side of Saint-Lusson as he plants the arms of France at Sault Sainte Marie. Joining his brothers in the fur trade, his exploring dreams were nurtured, and employed by the French Colonial Governor General Frontenac (Louis de Buade de Frontenac), he was the first white man to explore the Mississippi along with Jacques Marquette in 1673. Traveling from Michilimackinac down Lake Michigan to Green Bay where they too the Fox River to the portage to the Wisconsin River which drains into the Mississippi. They followed the Mississippi downstream until past the mouth of the Arkansas River when they turned back north, suspecting they were reaching areas of Spanish influence. They returned to Green Bay after a journey of 2,500 miles through lands previously uncharted by Europeans.

Shortly after his return, Jolliet was married to Claire-Francoise Bissot. In 1680 he was granted the Island of Anticosti, where he erected a fort. In 1693 he was appointed "Royal Hydrographer", and on April 30, 1697, he was granted the seigneury (fiefdom) of Jolliet, southwest of Quebec City, making him a minor "lord", roughly the colonial equivalent of a hereditary baronet with the title of "Sieur Jolliet" (Sir Jolliet). Louis Jolliet died some time in the month of May, 1700, being lost on a trip to one of his land holdings.

Jolliet was one of the first people of European descent born in North America to be remembered for significant discoveries. Jolliet is a relatively familiar historical figure in both the United States and Canada. Though no authentic period portrait is known to exist Jolliet is often portrayed wearing either typical frontiersman garb consisting of Davy Crockett style buckskins and fur hat or in sharp contrast, ensconced in the European nobleman's accoutrement his personal wealth and prestige would have commanded when living in colonial society.

As is the case with Jacques Marquette, Governor General Frontenac and La Salle, Louis Jolliet's legacy is most tangible in the Midwest (US) and Quebec (Canada), mostly through geographical names. Most notable among these include the cities of Joliet, Illinois, Joliet, Ohio and Joliette, Quebec which was founded by one of Jolliet's descendants, Barthélemy Joliette. Discrepancies in the spelling of the original name of "Jolliet" reflect interpretations based on pronunciation at times when illiteracy was common.

Louis Jolliet died at an unknown location in Canada while on a trip to one of his land holdings. His remains were never found.

*French colonization of the Americas *New France

*Jolliet 1645-1700 *Biography at the Dictionary of Canadian Biography Online *Joliet's map of New France, 1674 *2006 Expedition following Jolliet's journey down the Mississippi