This report is published as a product of the National Waste Terminal Storage (NWTS) program. The objective of this program is the development of terminal waste storage facilities in deep, stable geologic formations for high-level nuclear wastes, including spent fuel elements from commercial power reactors and transuranic nuclear waste for which the federal government is responsible. Pertinent environmental and geological information for the Gulf Interior Region (GIR) is summarized, including physical, biological, and cultural characteristics of the. region.