Over 50 smaller streams contained in 18+ miles of known passages combine in the main river passage to create America's longest navigable underground river. Living in the miles of flowing streams are rare blind cavefish and blind crayfish. Passengers on the custom electric tour boats can usually sight some of these unusual creatures as they float though the winding passages.
Cumberland Caverns is one of the most extensive known caves in Tennessee. Portions of this caving system were originally known as Higgenbotham Cave and Henshaw Cave. Considerable exploration of previously unseen sections along with integration of the two caves substantially enlarged the Caverns to the more than 32 miles that can be toured today.