Joseph Nicollet

Joseph Nicolas Nicollet, also known as Jean-Nicolas Nicollet, was a French geographer, astronomer, and mathematician known for mapping the Upper Mississippi River basin during the 1830s. Nicollet led three expeditions in the region between the Mississippi and Missouri Rivers, primarily in Minnesota, South Dakota, and North Dakota.

Before emigrating to the United States, Nicollet was a professor of mathematics at Collège Louis-le-Grand, and a professor and astronomer at the Paris Observatory with Pierre-Simon Laplace. Political and academic changes in France led Nicollet to travel to the United States to do work that would bolster his reputation among academics in Europe. He was elected a member of the American Philosophical Society in 1842.

Source: Wikipedia