Whitefish Lake was named in the 1850s for the abundant mountain whitefish harvested there. The Salish referred to the lake as epɫx̣ʷy̓u, "has whitefish".
Geography
Whitefish Lake is located northwest of the city of Whitefish, Montana at an elevation of. It lies between the southwest flank of the Whitefish Range and the northeast flank of Lion Mountain in Flathead County. This natural lake has a maximum length of and width of, and is at its deepest. Whitefish Lake has a surface elevation of and occupies a surface area of approximately. Tributaries to the lake include Swift Creek, which originates in Upper Whitefish Lake, and Lazy Creek, which enter at the northwestern head of the lake, and Hellroaring Creek on the eastern shore, and Beaver Creek which begins in Beaver Lake on the western shore. The lake has approximately of shoreline. The lake's outflow is the Whitefish River, which is a tributary to the Stillwater River, which flows into the Flathead River about east of Kalispell.
Ecology
and westslope cutthroat trout were the apex predator and pelagic surface feeder, historically, in Whitefish Lake. They persist in the lake but in greatly diminished numbers. The primary threat to native cutthroat trout is hybridization with non-native rainbow trout. Other native fish species include the river's namesake mountain whitefish, largescale sucker, longnose sucker, northern pikeminnow, peamouth chub, redside shiner, fathead minnow, and mottled sculpinslimy sculpin, and shorthead sculpin. The lake's fish assemblage has been almost completely disrupted by twentieth century introductions of non-native fishes and mysis shrimp. Introduced non-native fish species include northern pike which preys on native trout species. Kokanee salmon, the landlocked form of sockeye salmon, were introduced to the lake in 1945 and spawned successfully for 35 years until competition for forage with introduced mysis shrimp and predation from lake trout extirpated the kokanee. The rise in Mysida populations led to an increase in non-native lake trout numbers, the latter competing with bull trout and a predator of almost every native fish species in the lake. Non-native rainbow trout and brook trout have also been introduced and compete with native bull and cutthroat trout. Introduced lake whitefish are now abundant in the lake. ''
