A digital three-dimensional hydrogeologic framework model (HFM) represents the geometry and extent of hydrogeologic units (HGUs) and major structures in the Death Valley regional ground- water flow system (DVRFS). The HFM thickness data represent the geometry of the HFM by defining the thicknesses of the 27 HGUs in an approximately 45,000 square-kilometer region of southern Nevada and California (see "Larger Work Citation", Chapter E). The HGUs represent principal aquifers and confining units and are integral to the development of the DVRFS transient ground-water flow model (see "Larger Work Citation", Chapter F). The DVRFS framework and transient ground-water flow 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, for details).