Devils Hole and the pupfish are located in the Amargosa Desert ecosystem, in the Amargosa Valley, of southwestern Nevada, US, east of Death Valley and the Funeral Mountains and Amargosa Range. The Amargosa River is part of Devils Hole and the region's aquifer hydrology. Devils Hole is a water-filled cavern extending into a hillside. It is at an elevation of above sea level and the water is a constant temperature of . The surface area of Devils Hole is about 22 m long by 3.5 m wide (72 ft long by 11.5 ft wide). Its depth is at least . Devils Hole "may be the smallest habitat in the world containing the entire population of a vertebrate species". Approximately deep on one end of Devils Hole is a small rock shelf of . The dissolved oxygen of the water is 2.5–3.0 ppm up to around in depth, though the shallow shelf can have dissolved oxygen levels as high as 6.0–7.0 ppm in June and July.