It enters the Missouri at Sioux City, and is named for Charles Floyd,[3] a member of the Lewis and Clark Expedition.

The Floyd River rises in northwestern O'Brien County near the town of Sanborn and flows generally southwestwardly through Sioux, Plymouth and Woodbury counties, past the towns of Sheldon, Hospers, Alton, Le Mars, Merill, and Hinton.

[4] Charles Floyd, for whom the river is named, was a U.S. Army sergeant who was born in Kentucky and was one of the first to enlist in the Lewis and Clark Expedition.

[5] On August 19, 1804, just three months into the two-year journey, Floyd became violently ill and died the next day of what is believed to have been a ruptured appendix.

[7] Floyd was the expedition's only casualty, despite the many dangers encountered in the 8,000 miles traveled in reaching the Pacific Ocean and returning to St.