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Desertification has been defined as land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities (United Nations, 1992). A technique for identifying and assessing areas at risk for desertification in the arid, semi-arid, and subhumid regions of the United States was developed by the Desert Research Institute and the U.S. Environmental Protection Agency (EPA), using selected environmental indicators integrated into a Geographic Information System (GIS). Five indicators were selected: potential erosion, grazing pressure, climatic stress (expressed as a function of changes in the Palmer Drought Severity Index [PDSI]), change in vegetation greenness (derived from the Normalized Difference Vegetation Index [NDVI]), and weedy invasives as a percent of total plant cover. The data were integrated over a regional geographic setting using a GIS, which facilitated data display, development and exploration of data relationships, including manipulation and simulation testing. By combining all five data layers, landscapes having a varying risk for land degradation were identified, providing a tool which could be used to improve land management efficiency.