The Lahontan cutthroat trout, Oncorhynchus clarkii henshawi, is a race of the cutthroat trout native to the Lahontan Basin of Oregon, California, and western Nevada. It has been introduced and become established in the Pilot Peak Range of western Box Elder County, Utah. The Lahontan cutthroat trout is a Federally listed threatened species.
The Lahontan cutthroat trout is the largest of all cutthroat races. Like other cutthroat races, the Lahontan cutthroat is an opportunistic feeder, with the diet of small individuals dominated by invertebrates, and the diet larger individuals composed primarily of fish.
The Lahontan cutthroat trout is adapted to live in saline and alkaline lakes and streams. It is now very rare, currently occurring in only a small percentage of its native range. Major threats to the Lahontan cutthroat trout include the loss and alteration of spawning habitat, competition with nonnative fishes, and hybridization with nonnative trout.