This digital data set defines the lateral boundary and model domain of the area simulated by the transient ground-water flow model of the Death Valley regional ground-water flow system (DVRFS). The DVRFS transient ground-water flow model is 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). The model domain is an approximately 45,000 square-kilometer region of southern Nevada and California. The lateral boundary encompassing the model domain is a combination of no-flow boundaries resulting from physical barriers or hydraulic separation of flow regimes (ground-water divides and [or] regional flow lines) and arbitrary lateral-flow (throughflow) boundaries where ground-water flows across the lateral boundary. The lateral boundary is subdivided into 12 segments to reflect boundary conditions.