Lahontan cutthroat trout inhabit a wide range of habitats from cold, high-elevation mountain streams in California to lower-elevation and highly alkaline desert lakes in Nevada. They once occupied a vast range east of the Sierra Nevada but have been extirpated from nearly 95 percent of their native habitat in California. Their range extends from the Sierra Nevada crest in California northeast into Nevada, including a small portion in Oregon.
In California, the historic range of Lahontan cutthroat trout includes Lake Tahoe and the Carson, Truckee, and Walker river basins. Reports from settlers in 1853 assert Lahontan cutthroat trout were abundant in the Susan River as well.
Introduction of non-native trout into the four primary watersheds that comprise their native range in California, along with extensive habitat alteration from human land use activities, caused their extirpation from most of their former range. Most self-sustaining populations are located in isolated headwater streams and are the result of reintroduction efforts. State fish hatcheries have been increasing their production and stocking of Lahontan cutthroat trout to expand fishing opportunities for this species in accessible waters within their native drainage.