Fly Fishing in Montana on Harrison Lake
Harrison Lake is about an hour west of Bozeman, near Harrison in Madison County. Often referred to as Willow Creek Reservoir, this 700+ acre stillwater is fed by a few small streams in the Jefferson River drainage, including both Willow and Norwegian creeks. Panoramic views of the Tobacco Root and Madison Mountain ranges make for some idyllic mornings during the springtime. A popular Montana fly fishing day trip destination for local and visiting anglers.
Montana Fish, Wildlife, and Parks actively manages the reservoir for anglers with stockings of Rainbow Trout and Kokanee Salmon. Brown and Westslope cutthroat trout are also present throughout the reservoir.
Spring and early summertime are the best times of the year to fly fish Harrison Lake. Expect calm mornings with winds picking up in the late mornings throughout the year.
Fishing Overview
The reservoir is popular with a mixed user group of anglers, with conventional tackle anglers far outnumbering fly anglers. During the springtime, rainbow trout can be found in good numbers around points next to deep water and in the shallow bays to the north and south of the public boat ramp.
Anglers fly fishing in the reservoir use float tubes and boats to cover the best areas of the lake. Floating enables anglers to reach the transition zones between depths where trout most actively feed. Fly fishing from the shore is rarely productive as reservoir levels are generally high in the springtime and well below the banks by mid-summer.
Harrison Lake Fly Fishing Strategies
Indicator nymph rigs are most effective in spring, usually consisting of a balanced leech followed by a chironomid dropper. Anglers vary the length of their leader depending on the depth at which the fish are most active – overall length can be up to 15’ between the strike indicator and first fly during the spring. Slip strike indicators are incredibly helpful to anglers fishing lakes and reservoirs, with these setups favored by lake fly fishermen in the early season.
Leeches, crayfish, damselflies, and small baitfish patterns are effective when fished with a full sinking fly line while floating or drifting along deep edges. A class III or intermediate sinking line is optimal for covering the most productive zones of 5-15’ in depth. Trail a bead-head hares ear or damselfly nymph behind a weighted wooly bugger to prospect these mid-depth zones during times when fish aren’t actively feeding on hatching insects.
Grass and algae become problematic for the fly angler armed with sinking fly lines by early summer in the shallow bays and along the banks.
Explore Harrison Lake
The Willow Creek arm is isolated from the main body of the lake and has wake restrictions during the daytime. Recreational traffic is lighter here, and the scenery is spectacular, with juniper-tree-lined cliff walls surrounding the eastern banks. Trout hold in the deep channels in this part of the lake and are tough to reach with a fly.
Prospecting along the cliff edges with streamers and large terrestrials or mice patterns can be productive during the late season.
The dam is located near the northeast corner of the lake, below which is a private tailwater fishery referred to as “Willow Creek.” There is no legal access to Willow Creek from the reservoir.
Summertime on Harrison Lake
The lake becomes increasingly popular with recreational users, including personal watercraft and water skiers, as the summer progresses. Trout move to deep water as traffic and water temperatures increase and are typically well beyond the reach of the fly angler.
Anglers will find that the early morning hours are quiet in late July and August, with rising trout feeding on callibaetis and trico mayflies. Hatches here are sparse when compared to other stillwater fisheries favored by anglers fly fishing in Montana, such as Ennis, Hebgen, and Quake lakes. In general, Harrison Lake receives very little attention from fly anglers after July 1.
Reservoir levels drop throughout the summer with increased, downstream irrigation demands. The exposed dirt banks are suitable for launching a small boat into the fall during dry weather. As the levels drop, the lack of structure can make it difficult to locate trout for the fly angler. Fishing becomes more productive with conventional tackle and trolling anglers throughout the summer and fall.
Harrison Lake Fly Fishing Trips
Stillwater fishing is a great option during the high water season and offers some of the best fly fishing near Bozeman from mid-May through early June. Harrison Lake has long been known for producing hard-fighting rainbow and brown trout commonly found in the 16-20” range. Indicator fly fishing around the bay mouths is a nice way to “mix things” up during this time of the year and is always a popular choice with our Montana fishing guides when local rivers are high and dirty.
We have been a Montana fly fishing outfitter in Bozeman for over two decades. When water conditions are tough on the Montana rivers near Bozeman in late spring and early summer, we rely on "off the beaten path" streams and reservoirs like Willow Creek Reservoir. Guided fly fishing trips here are best suited for intermediate or advanced fly fishermen comfortable with deep-water indicator and streamer fly fishing.
E-mail our Montana fly fishing experts to learn more about our guided fly fishing trips near Bozeman and our Harrison Lake fly fishing day trips.