The McCloud River redband trout (Oncorhynchus mykiss stonei) is one of three redband trout subspecies of the rainbow trout in the family Salmonidae. The trout is native in small tributaries of the McCloud River and Pit River which are tributaries of California's Sacramento River. Its historic range has declined significantly since it was first described in 1894. Remaining populations of genetically pure McCloud River redband trout are threatened by predation, habitat loss, competition with introduced trout species and by hybridization with hatchery rainbow trout introduced to support sport fishing .