Incredibly, on the dangerous journey into the unknown undertaken by the Corps of Discovery, only one man died. Sergeant Charles Floyd died from a medical condition, described as "bilious colic" in the expedition journals, which most historians agree was probably a ruptured appendix. At that time, there was no cure for appendicitis, so Floyd would most likely have died regardless of his surroundings.

Today, there is a large monument in Sioux City, Iowa, that has been erected in honor of Floyd. This stone obelisk rises 100 feet high, second only in size to the Washington Monument; Floyd's remains are sealed in its concrete core. In 1960, the Floyd Monument was named the nation's first National Registered Landmark.