The Tucson basin, located in southeastern Arizona, underlies a rapidly growing metropolitan area. Because of Tucson's rapid growth and because it's economy relies heavily upon the aerospace, agriculture, defense, education, electronics, mining, and tourism industries, significant opportunities exist for direct-heat utilization of geothermal water. Geothermal energy could have economic impact by stabilizing energy costs to resource users. The purpose of this report is to outline known occurrences of thermal (>300 degree C) water around Tucson. Identification of the main geologic and geohydrologic features which determine the temperature distribution beneath Tucson provides a basis to formulate geologic models which have use in exploration and evaluation of area resources. (66 pages)