A preliminary assessment of the geothermal potential of the western half of the northern Hassayampa Plain has been made. A single shallow well with a measured temperature of 51/sup 0/C initially called attention to the area. Field investigations were carried out between January and July, 1979. The field program consisted of (1) temperature logging of available water wells and mineral test holes, (2) collecting soil samples for mercury analysis, (3) taking water samples for major cation and anion analyses, and (4) conducting reconnaissance geologic mapping along the northeast side of the Belmont Mountains. Parts of this report are taken from published maps and reports and from unpublished field investigations conducted in 1972 to 1973.