Peacock Springs cave system

A long, mapped underwater cave beneath Wes Skiles Peacock Springs State Park in north Florida, entered by certified divers at Peacock Springs and Orange Grove Sink under state park rules.

The Peacock Springs cave system lies under Wes Skiles Peacock Springs State Park, a small, quiet park near Luraville in north Florida. The park holds two major springs, a spring run and six sinkholes, and the water-filled passages that link them run beneath a mature hardwood and pine forest. Florida State Parks describes the system as one of the longest underwater caves in the continental United States.

The first recorded cave dive here was in 1956, and divers have been mapping the passages ever since. By the end of the 1970s, members of the NSS Cave Diving Section had surveyed about 20,000 feet, then the longest known system of its kind. The park now cites roughly 33,000 feet of surveyed passage and says new discoveries are still being made.

Divers know the system by its landmarks: the Breakdown Room, a passage whose floor is piled with rock fallen from the ceiling; the Peanut Restriction, where passages narrow (a restriction is a tight spot that a diver must pass carefully); the Crypt, named for turtle bones found there in 1975; and Olsen Sink, a karst window where daylight reaches the water through a collapsed sinkhole. Diving is allowed only from Peacock Springs and Orange Grove Sink, and only within the limits of each diver's training.

Above ground, a 1.2-mile interpretive trail traces the route of the caves below, with displays showing maps and photographs of the passages. The caves are also home to cave-adapted animals such as the pallid cave crayfish and the Florida cave amphipod.

The cave formed in limestone laid down when Florida lay beneath a shallow sea during the Eocene; slightly acidic rainwater dissolved fissures and hollows in the rock that grew into the present passages. Florida State Parks counts five second-magnitude springs in the park: Peacock Springs I, II and III, Bonnet Spring and Orange Grove Sink.

The park's springs are second-magnitude, which Florida State Parks defines as discharging roughly 10 to 100 cubic feet (about 0.3 to 2.8 cubic metres) of water per second. The park notes that water levels in the springs vary, and swimming and snorkelling depend on seasonal water levels.

The system has been explored since 1956 and was the world's longest known system of its type at the end of the 1970s, according to the NSS Cave Diving Section. The park was renamed in 2011 to honour Wes Skiles, a cave diver, explorer and filmmaker who campaigned to protect it and Florida's springs.

Florida State Parks names three main entrances to the cave system, and also mentions the Pothole and Olsen Sink as openings into it. Park rules allow divers to enter and surface only at Peacock Springs and Orange Grove Sink, except where necessary for safety.