Mount Otto is set 21 miles (34 km) east of the Continental Divide in the Sangre de Cristo Range which is a subrange of the Rocky Mountains.

It is the fifth-highest summit in Fremont County and can be seen from Highway 285 near the community of Villa Grove.

Topographic relief is significant as the summit rises 4,200 feet (1,280 m) above the San Luis Valley in two miles (3.2 km).

[7] Due to its altitude, it receives precipitation all year, as snow in winter, and as thunderstorms in summer, with a dry period in late spring.

The mountain's toponym was officially adopted in 1970 by the United States Board on Geographic Names to commemorate Otto Mears (1840–1931), early pioneer in the San Luis Valley and interpreter-negotiator for early Indian treaties, developer of roads, railroads, and mining and milling operations in the San Juan Mountains region.