 Cutthroat trout were given the name "Salmo clarki" in honor of William Clark, who co-led the expedition of 1804–1806.One of Lewis and Clark's missions was to describe the flora and fauna encountered during the expedition.The type specimen of "S. clarki" was described by naturalist John Richardson in 1836 from a tributary of the lower Columbia River, identified as the "Katpootl", which was perhaps the Lewis River as there was a Multnomah village of similar name at the confluence.