Mammoth Cave National Park

Mammoth Cave formed in thick limestone capped by sandstone in south-central Kentucky, and people have been entering it for at least 5,000 years. Native Americans left cane torches, gourd fragments and woven grass slippers in the Salts Cave section, and mummified burials have been recovered from caves in the region. In 1935 the remains of a pre-Columbian miner were found under a boulder that had shifted onto him; he was named Lost John.

The land at the historic entrance was registered in 1798. When the Embargo Act of 1807 and the War of 1812 cut off imported saltpetre, the cave was mined for nitrate on an industrial scale by 70 enslaved labourers, and after the war it turned to tourism. Stephen Bishop, an enslaved guide from 1838, was the first to cross the Bottomless Pit and one of the first to map the cave extensively. In 1839 John Croghan bought the estate together with Bishop and its other enslaved workers, and in 1842 to 1843 he ran a short-lived tuberculosis hospital inside the cave.

In the early 20th century rival cave owners fought over visitors, and the death of the explorer Floyd Collins, trapped in Sand Cave in 1925, became a national media sensation. The park was authorised on 25 May 1926; thousands of residents were moved out, often through bitter eminent domain proceedings, and it was established on 1 July 1941. On 9 September 1972 explorers linked Mammoth Cave to the Flint Ridge system, and by 2025 more than 686 km of passages had been surveyed, the longest known cave system in the world. It was inscribed as a World Heritage site in 1981.