Hot springs about 2 km northeast of the railroad siding of Trego (Sec. 31 T34N, R26E) are located along the railroad tracks and have a reported temperature of 86°C (Mariner and others, 1974; Grose and Keller, 1975b). The spring has been called Butte Hot Spring or Trego Hot Spring, and is clearly visible on airborne thermal infrared (Grose and Keller, 1975b). Various chemical geothermometers indicate a thermal reservoir temperature of 120-128°C (Mariner and others, 1974; Grose and Keller, 1975b). Warm water wells are located in the vicinity of Garrett Ranch (Sec. 10, T33N, R25E) about 5 km southwest of Trego Hot Springs and 3 km southwest of Trego siding. These wells have temperatures of up to 52°C (Sinclair, 1963a). Coyote Spring (Black Rock) to the north of the ranch about 2 km has a temperature of 22°C, according to Grose and Keller (1975b), although Sinclair (1963a) reported a temperature of 16°C. Coyote Spring is dry according to the Trego 7.5-minute topographic map (1980). Trego Hot Ditch, located adjacent to the hot springs, reportedly has a temperature of 31.1ºC and is used for bathing (Williams, 1996, p. 20-21). The springs at the Trego area are associated with a fault along the edge of the Black Rock Desert (see figure) which connects with a long fault zone along the west side of the Black Rock Range (L. T. Grose, written commun., 1977). The geology of Trego Hot Springs is discussed by Davis (1983).