About midway below Saylorville and above Ottumwa, near Pella, the river is impounded to create the Lake Red Rock reservoir.

Early French explorers named it La Rivière des Moines, literally meaning "River of the Monks."

[citation needed] William Bright writes that Moines was an abbreviation used by the French for Moingouena or Moingona, an Algonquian subgroup of the Illinois people.

The Native American term was /mooyiinkweena/, a derogatory name applied to the Moingouena by the Peoria people, a closely related subgroup.

The meaning of the native word, according to an early French writer, is visage plein d'ordure, or in plain English, "shit-face", from mooy-, "shit", -iinkwee, "face", and -na, "indefinite actor".

[7] The 1718 Guillaume Delisle map (pictured) labels it as "le Moingona R." During the mid-19th century, the river supported the main commercial transportation by water across Iowa.

[8][9][10] Major flooding in 1851 occurred in Bentonsport, Croton, Bonaparte, Des Moines, Eddyville, Farmington, Iowaville, Keosauqua, Muscatine, Oskaloosa, Ottumwa and Rochester.

[11] The Great Flood of 1993 on the river and its tributary the Raccoon, in the summer of 1993, forced the evacuation of much of the city of Des Moines and nearby communities.