This digital dataset represents the surface hydrogeology of an approximately 45,000 square-kilometer area of the Death Valley regional ground-water flow system (DVRFS) in southern Nevada and California. Faunt and others (2004) constructed the map by merging mapped lithostratigraphic units into 27 hydrogeologic units (HGUs). The HGUs represent rocks and deposits of considerable lateral extent and distinct hydrologic properties. The hydrogeologic map was fundamental to the development of a hydrogeologic framework model and a transient ground-water flow model of the DVRFS. These models are the most recent in a number of regional-scale models developed by the U.S. Geological Survey (USGS) for the U.S. Department of Energy (DOE) to support investigations at the Nevada Test Site (NTS) and at Yucca Mountain, Nevada (see "Larger Work Citation", Chapter A, page 8).