The Amargosa River is an intermittent stream, approximately 200 mi (320 km) long, in southern Nevada and eastern California in the United States. It drains a high desert region northwest of Las Vegas into Death Valley, where it disappears into the ground. Except for 1) a small portion of its route in the Amargosa Canyon in California, 2) a small portion at Beatty, Nevada, the river flows only after a rare rainstorm washes the region.
It rises in Nye County, Nevada, along the southern side of Pahute Mesa in the Nellis Air Force Range. When carrying water, it flows southwest, crossing the Sarcobatus Flats and passing the town of Beatty. At Beatty it turns southeast to flow across the Amargosa Desert along the east side of the Funeral Mountains. It crosses into eastern California, along the east side of the Amargosa Range, passing through the 20 mi (32 km) Amargosa Canyon. It enters the northern Mojave Desert where it passes west along the southern side of the Amargosa Range, then turns north in a U-shape, flowing along the western side of the range and entering the southern end of Death Valley. It flows northward through the basin to the center of the valley, disappearing into the ground near Badwater Basin to feed to the aquifer that is the remnant of prehistoric Lake Manly. The lower course of the river in Death Valley is within Death Valley National Park.
The name of the river is Spanish for "bitter", probably shortened from agua amargosa, "bitter water". The river is an ancient stream, following an antecedent canyon. Evidence of human habitation along the river goes back approximately 10,000 years to the end of the last ice age, when the area was much wetter. In addition to prehistoric Lake Manly in Death Valley, the middle river valley was submerged during the late Pleistocene by prehistoric Lake Tecopa. The canyon floor along the Amargosa Range has remnants of indigeneous habitations that are protected by the Bureau of Land Management. The Old Spanish Trail followed the course of the river in the 19th century. From 1907 to 1941, the Tonopah and Tidewater Railroad followed the lower course of the river serving remote Death Valley communities.
The section of the river where it flows perennially is in the Amargosa Canyon along the southeast end of the Amargosa Range near the town of Shoshone, California. Along a 20 mi (32 km) stretch in the Amargosa Canyon it sustains a small margin of riparian wetlands in the surrounding desert. The water, as the name suggests, is non-potable by humans but is a critical source of water for the area wildlife in this section.