Northwest Montana contains hands down the largest collection of lakes in the state. And while some of these are man-made reservoirs, most are natural lakes. While the fishing tends to be quite good, it can be difficult for fly anglers because of the great depths of many of these lakes. Tally Lake near Whitefish reaches a depth of almost 500 feet, making it the deepest in the state. Nevertheless, there are opportunities for fly anglers.
One of the largest natural lakes in the west, Flathead boasts nearly 200 square miles of surface area. Once a prolific producer of native Cutthroats and Bull Trout, these populations have been significantly reduced by the introduction of non-native species over the years, most notably Lake Trout. Flathead still offers good fishing options, especially to those who have access to a boat.
Located 15 miles south of the entrance to Glacier National Park from Highway 2, Hungry Horse Reservoir is a 34 mile long reservoir noted more for its water recreation sports than for fishing. Nonetheless, anglers targeting smaller cutthroats in secluded bays with beautiful beaches and stunning scenery do well from May until October. The South Fork of the Flathead drainage and Hungry Horse Reservoir is one of the few watersheds in Montana where healthy populations of Bull Trout and Westslope Cutthroats exist without the threat of non-native trout species.
Straddling the border with 48 miles in Montana and 42 miles in British Columbia, Lake Koocanusa was formed with the creation of the Libby Dam in 1971. The lake is immense and offers very marginal shore fishing. The principal draw is the prodigious numbers of kokanee salmon ranging from 11 to 14-inches. Large kamloop rainbows lure boat fishers from all around the region. Boaters will find plenty of water to fish with over 46,000 surface acres.
The Thompson Chain of Lakes, stretching along Highway 2 for 17 miles between Libby and Kalispell, quite possibly offers more fishing variety than any other stretch of highway in Montana. Nineteen lakes ranging in size from three acres to 1,300 acres, the chain boasts both warm-water game fish and cold-water trout.