Geothermal energy exploration is being conducted at several locations in the United States including a site at Roosevelt Hot Springs in southwest Utah. To assess any possible impact and to help design a monitoring strategy for geothermal development, element concentrations in animal tissues and selected animal population characteristics were determined at Roosevelt Hot Springs for the 1977-1978 period. The information can be used as baseline data as it was collected before any extensive industrial development had taken place. Concentrations of barium, boron, cadmium, chromium, copper, iron, lead, manganese, strontium and zinc were determined for livestock and wildlife samples. In some cases, concentration values for additional elements (e.g., arsenic, lithium, magnesium, potassium and sodium) were also established. Small mammal populations (primarily rodents and lagamorphs) were also characterized as part of the effort to conduct baseline surveys prior to extensive geothermal development. Objectives of the limited population survey were to present information on habitat associations and species diversity as well as to provide an estimate of animal abundance both adjacent to and distant from the KGRA (Known Geothermal Resource Area).