Louis Jolliet was a French-Canadian explorer born in 1645. He is best known for his significant role in the exploration of North America, particularly the Mississippi River. Jolliet, along with the Jesuit priest Jacques Marquette, embarked on an expedition in 1673 that aimed to map the river and its tributaries, contributing to European knowledge of the region. During their journey, Jolliet and Marquette traveled from Lake Michigan down the Mississippi River to the Arkansas River. Their exploration provided valuable information about the geography and indigenous peoples of the area. Jolliet's work laid the groundwork for future exploration and settlement in the Mississippi Valley.