Native Americans referred to the mountain range as “ah-sah-tah,” meaning bighorn. Lewis and Clark adopted the name Bighorn River after they encountered large bands of big horn sheep at its mouth. It is undisputed that the Bighorn Mountains once supported large numbers of bighorn sheep. Unfortunately, the great bands in the Bighorn Mountains are now only references in history books. Like so many places that once had booming populations of bighorns; competition with livestock, habitat loss, disease and unregulated hunting contributed to the extirpation of bighorns from the Bighorn Mountains shortly after the turn of the century.