Death Valley Earth at 134 °F (56.7 °C) on July 10, 1913, as well as the highest recorded natural ground surface temperature on Earth at 201 °F (93.9 °C) on July 15, 1972. Located near the border of California and Nevada, in the Great Basin, east of the Sierra Nevada mountains, Death Valley constitutes much of Death Valley National Park and is the principal feature of the Mojave and Colorado Deserts Biosphere Reserve. It is located mostly in Inyo County, California. It runs from north to south between the Amargosa Range on the east and the Panamint Range on the west; the
Death Valley pupfish is 4 times more saline than the ocean, hot water up to , and cold water down to . This species is known from only two locations in Death Valley: Salt Creek (subspecies "salinus") at about 49 meters below sea level, and Cottonball Marsh (subspecies "milleri"), at about 80 meters below sea level. They are thought to be the remainders of a large ecosystem of fish species that lived in Lake Manly, which dried up at the end of the last ice age leaving the present day Death Valley. The Salt Creek subspecies is also found at River Springs and