Piegan Blackfeet
Because Yogo Gulch lies in a region historically inhabited by the Piegan Blackfeet people, promoters of Yogo sapphires claim that "yogo" may mean "romance" or "blue sky" in the Blackfoot language, although there is little evidence to support this claim. Other meanings for "yogo" have been suggested, including "Going over the hill". The meaning of the word "Yogo" had been lost by 1878, when placer gold was found in Yogo Creek. Thus, its true meaning is uncertain.