Global Range: Historically abundant in lakes and streams throughout the physiographic Lahontan basin of northern Nevada, eastern California, Oregon, and Utah; currently exists in about 0.4% of former lake habitat and 11% of former stream habitat within the native range; Independence and Summit lakes support the only remaining reproducing lacustrine form within the native range; has been introduced outside native range, primarily for recreational fishing purposes (USFWS 1994).
There are three distinct population segments: (1) western Lahontan basin (Truckee, Carson, and Walker river basins), (2) northwestern Lahontan basin (Quinn River, Black Rock Desert, and Coyote Lake basins), and (3) Humboldt River basin (USFWS 1994). Behnke (1992) regarded the Humboldt cutthroat as a distinct, undescribed subspecies and limited the range of the Lahontan cutthroat to the Lahontan basin exclusive of the Humboldt River system. He stated that the native range included Lake Tahoe, and Pyramid, Walker, Donner, Independence, and Summit lakes, and the Truckee, Carson, Walker, and Quinn rivers, noting that the Quinn River cutthroat may have been derived from the Humboldt River.
Humboldt cutthroat trout formerly occurred throughout the Humboldt River drainage of Nevada; now restricted to numerous small streams; occurs in Willow Creek Reservoir and Jiggs Reservoir during high-runoff years; early introductions resulted in the two known existing populations in the Smoky Valley basin; the correct subspecific allocation (Humboldt or Lahontan) of cutthroat trout in the Quinn River drainage is uncertain (Behnke 1992).
"Whitehorse cutthroat trout" is native to the Willow Creek and Whitehorse Creek drainages of Malheur and Harney counties, Oregon. A transplanted population occurs in Antelope Creek, a Whitehorse basin stream that was fishless prior to the 1971 transplant (Behnke 1992).
Native Lahontan cutthroat trout have been extirpated from Tahoe, Pyramid, Walker, and Donner lakes. The present population in Pyramid Lake derives from individuals of the same subspecies introduced from elsewhere (Summit Lake, Heenan Lake) in the Lahontan Basin (Echelle 1991, Behnke 1992). In Nevada, present range includes Pyramid Lake and the Truckee River (Washoe County), both forks of the Walker River and Walker Lake (Mineral County), Summit Lake, and Carson River and its tributaries (Douglas and Lyons counties). In California, occurs in the headwaters of the Walker River (Mono County), and Catnip and Heenan reservoirs. In the late 1980s, fishes salvaged from drought-depleted sections of By-Day Creek in Mono County, California, were used to restock Slinkard Creek (Matthews and Moseley 1990).