Aeromagnetic and gravity surveys were conducted in the Black Rock Desert, Utah to assess the geothermal potential of the Meadow-Hatton Known Geothermal Resource Area (KGRA). The presence of basalt flows less than 1000 yr old and a 400 000 yr old rhyolite dome suggested that a hot intrusive body, which should be detectable in both types of potential field data, may provide the heat source for hot springs in the study area. A simultaneous inversion computer program was developed as part of this study to model these potential field data. The resulting models indicate hydrothermal alteration about the hot springs extending to a depth of approximately 1 km. Normal faults above a low-angle detachment appear to reach a depth of approximately 4 km and provide a path for the circulation of groundwater in the area. No evidence for a buried igneous body was found in the study area, and it is therefore concluded that the migration of fluids along the deep faults is sufficient to account for the water temperatures estimated for the KGRA.