Mount Otto is a prominent 12,865-foot peak in Colorado’s Sangre de Cristo Range, straddling the Fremont and Saguache county line within the Sangre de Cristo Wilderness. Rising 4,200 feet above the San Luis Valley in just two miles, it has especially dramatic relief on its west side and forms a divide between waters flowing to San Luis Creek and toward the Arkansas River. Visible from Highway 285 near Villa Grove, it is the fifth-highest summit in Fremont County. Its official name, adopted in 1970, honors Otto Mears, a major early regional builder, negotiator, and transportation developer closely tied to nearby Poncha Pass and the San Luis Valley.