National park, southwest-central Kentucky, U.S. The park, authorized in 1926 and established in 1941, occupies a surface area of 82 sq mi (212 sq km) that covers a system of limestone caverns.
In 1972 a passage was discovered linking the Mammoth Cave and the Flint Ridge Cave System; the explored underground passages have a combined length of some 329 mi (530 km). The caves are inhabited by various animals that have undergone evolutionary adaptation to the dark, including cave crickets, blindfish, and blind crayfish. Mummified Indian bodies, possibly of pre-Columbian origin, have been found in the caves.