Floyd Collins (July 20, 1887 - February 17, 1925) was a cave explorer and guide in central Kentucky. He is noted for having discovered Crystal Cave on January 18, 1917, and is sometimes referred to as "The Greatest Caver Ever Known."

The Collins family owned Crystal Cave , a small tourist cave in the same general area as Mammoth Cave. Floyd was intent on finding another entrance into Mammoth in order to attract tourists to increase the meager traffic that they received. While doing so, Floyd became trapped in Sand Cave on January 30, 1925 as his light went out, causing him to knock loose a large rock, pinning his leg. It was later discovered that the actual rock that pinned his leg weighed only 12 kilograms (26-1/2 pounds), but was wedged in such a manner that neither he nor the rescuers could reach it.

Trapped only 50 meters from the entrance, the attempt to rescue Collins degraded into a carnival-like atmosphere at the surface. Shortly after the media arrived, vendors came to feed tourists. While trapped, a light bulb and hot food could be brought to Collins. Reporter Skeets Miller crawled into the cave to interview him. A shaft that was dug to get to the passage under Collins collapsed, and Collins died by the time a second shaft was completed. By that time, 18 days had elapsed. Collins had died the day before.

Deciding it was too dangerous to remove the body, the rescuers left. 80 days later, Floyd's brother Homer and some friends retrieved the body, which was kept in a glass-topped coffin in Crystal Cave for many years. Before being interred permanently in Flint Ridge Cemetery in 1989, the body was stolen from Crystal Cave, and recovered—missing one leg—after which point it was kept in a more secluded portion of Crystal Cave in a chained casket. Eventually, Crystal Cave was absorbed by the National Park Service, and closed to the public.

The life and death of Floyd Collins has inspired a musical by Adam Guettel, as well as at least one film documentary, several books, a museum, and untold numbers of tales and short songs by cavers. The Big Carnival is a 1951 movie loosely based on the media circus surrounding the events.