This map covers the southern part of the Funeral Mountains, and adjacent parts of four structural basins - Furnace Creek, Amargosa Valley, Opera House, and central Death Valley. It extends over three full 7.5-minute quadrangles, and parts of eleven others - a total area of about 950 square kilometers. The boundaries of this map were drawn to include all of the known proximal hydrogeologic features that may affect the flow of ground water that discharges from the springs of the Furnace Creek wash area, in the west-central part of the map. These springs provide the major potable water supply for Death Valley National Park.