Devils Hole

Devils Hole is a geologic formation located within the Ash Meadows National Wildlife Refuge, in Nye County, Nevada in the Southwestern United States.

Devils Hole—a detached unit of Death Valley National Park—is habitat for the only naturally occurring population of the endangered Devils Hole pupfish (Cyprinodon diabolis). The 40 acre (16 ha) unit is a part of the Ash Meadows complex, an area of desert uplands and spring-fed oasis that was designated as a national wildlife refuge in 1984.

Devils Hole is a geothermal pool within a limestone cavern in the Amargosa Desert in the Amargosa Valley of Nevada, east over the Amargosa Range and Funeral Mountains from Death Valley. Its waters are a near constant salinity and temperature (92 °F or 33 °C). The cavern is over 500 feet (150 m) deep and the bottom has never been mapped.

Devils Hole branches into deep caverns at least 300 feet (91 m) deep from an opening at the surface that is approximately 6 by 18 feet (1.8 by 5.5 m). According to geologists, the caves were formed over 500,000 years ago. The pool has frequently experienced activity due to far away earthquakes in Japan, Indonesia and Chile, which have been likened to extremely small scale tsunamis.

Devils Hole is the only natural habitat of the Devils Hole pupfish, which thrives despite the hot, oxygen-poor water. It is an IUCN Red List endangered species. The pupfish has been described as the world's rarest fish, with a population of less than 200 since 2005.Genetic information indicates that the pupfish species is as old as the Hole itself, which opened to the surface about 60,000 years ago.

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