Flathead Lake

Flathead Lake in northwestern Montana is the largest natural freshwater lake west of the Mississippi River — a massive, glacier-carved body of water stretching 28 miles long and 15 miles wide in the Flathead Valley between the Mission Mountains and Salish Mountains. The lake's extraordinary size, depth, and ecological diversity make it one of the most biologically significant freshwater systems in Montana. For fly fishers, Flathead Lake's most significant residents are the Westslope Cutthroat and Bull Trout that inhabit the lake's cold, clear waters and spawn in the tributary streams of the Flathead River system. These are conservation priority species — the Bull Trout in particular are fully protected throughout the Flathead drainage and their presence in catchable numbers is a powerful indicator of the lake's pristine water quality. Lake Trout (Mackinaw) provide the most accessible fly fishing in the lake's deeper sections, with fish averaging 5–20 pounds in the productive transition zones between the deep basin and the shallower shelf areas. Large Marabou streamers and tube flies can be highly effective for lake trout in fall when they move to the shallows for spawning. The lake's Kokanee Salmon — introduced and thriving — provide exceptional summer fishing opportunities, while the Westslope Cutthroat that enter the lake from Flathead River tributaries provide spring fly fishing in the river mouth areas. The combination of fishery diversity, spectacular scenery, and the wildness of the Mission Mountain backdrop makes Flathead Lake one of Montana's finest multi-species fishing destinations.