The U.S. Army will continue to be involved in desert warfare for the foreseeable future. It is imperative that military equipment is designed and tested for use in this environment; that soldiers are trained to operate in the desert; and that they can accomplish their missions under the extreme conditions presented by this distinct operating environment. Understanding desert processes and terrain is fundamental to accomplishing these goals. Scientists have long debated demarcation and classification of deserts, considering many measurable factors. However, few have classified deserts in a way that specifically supports the military missions of operating, training, and testing. This research was undertaken to classify deserts using both physical and military variables and to develop a system that examines deserts from a military perspective. A panel of scientists and military officers developed and tested a model of warm and hot desert classification. The robustness of the model was tested at the Yuma Proving Ground, Arizona, and the National Training Center at Fort Irwin, California. This work is a preliminary step toward a thorough examination of desert training and testing sites and potential conflict areas in desert locations throughout the world.