The first expedition commanded by John C. Fremont, called "The Pathfinder," was sent to map this river.
Yellowstone
Arkansas
Red
Des Moines
Des Moines River. While serving as a second lieutenant in the U.S. Army Bureau of Topographical Engineers, Fremont learned how to conduct scientific field work and how to properly record his findings while working with Joseph N. Nicollet’s surveying and mapping expeditions in the upper Mississippi and Missouri rivers, 1838 – 1839. In 1841, Fremont was put in command of a quick survey of the Des Moines river.