Great fishing prospects sometimes overshadow great fishing prospects. For example, to experience the exceptional fishing for westslope cutthroat trout in northwest Montana’s Upper Boulder Lake (aka Boulder Lake #1), you first have to ignore the Kootenai River’s tempting rainbows as you drive north from Libby, then refrain from rubbernecking the many enticing bays and inlets of Lake Koocanusa. But your rewards for staying the course are Boulder Lake’s high-mountains solitude and cooperative cutthroat that come at the modest price of an easy 2-mile backcountry hike.
I backpacked into Boulder Lake last September with my friend Jeff Talbert, right after a hard frost had made flying trout food scarce. After launching my backpack boat, I hooked, netted, and released fish after fish up to 16 inches long, using a size 12 Royal Wulff, my mountain lake dry fly of choice unless I catch a hatch. Talbert, new to the sport, had packed his new fly rod, and the fast fishing provided the perfect opportunity to get him hooked on fly fishing. I encouraged him to take a turn in the boat and fling a dry fly. He soon found himself attached to trout after trout. Another convert to fly fishing. For variety, we also tried subsurface fishing and enjoyed excellent results using Bigg’s Sheep Creek Specials and brown Gold Ribbed Hare’s Ear Nymphs, both in size 12.
I encouraged Talbert to fish to his heart’s content. But I actually started feeling a little guilty about all the trout I’d caught, even though I’d released them. How many fish does a guy need to catch? With a mortality rate of close to 5 percent for trout caught and released, I figured I’d killed two trout. I once met a fly fisher at a mountain lake and asked him about the fishing. He said it was pretty good and smiled as he told me how many trout he’d caught. I asked if he’d kept any to eat. “No,” he said. “I made my peace with trout a long time ago.” So have I, I thought. I’m at peace with eating a couple from a lake so richly populated, and they are a treat, especially cooked over a campground grill.
Given the ease of the hike into Boulder Lake, I expected company. However, only one other fisher made the trek, and he didn’t stay long. It’s a good thing I didn’t run into him later, though, or he might have gotten a snootful of bear spray. Accidentally, of course. While poking along the shoreline, I saw where he’d cleaned his catch and left the guts lying on a fallen log. There are few better ways to attract bears to your camp than leaving fish guts lying around. Northwest Montana is grizzly country, so Talbert and I bagged our food and hung it at night. Maybe I’m just cranky, but I’d rather not have a furry midnight visitor in my camp.
Fly fishing from shore is challenging at Boulder Lake. The shoreline is brushy, which makes anything but a roll cast difficult. In addition, the lake is mesotrophic, which translates to a soft bottom and substantial weed growth far out into the lake. A two-handed 5-weight rod would be an asset here. A better option is to pack in some type of floating device. Once out on the lake in my backpack boat, I found my 3-weight to be ideal.
To reach Boulder Lake #1, follow State Route 37 north from Libby. Continue 54 miles, and cross the bridge spanning Lake Koocanusa. After crossing the bridge, turn north onto Yaak Valley–Libby Dam Road (named Forest Service Road 228 on the USDA Rexford and Fortine Ranger District map) and continue about 3 miles. Turn south on Forest Service Road 337 and drive about 11 miles, then continue about a mile on Forest Service Road 7183 to the trailhead on the right. Forest Service Road 7229 is gated at the trailhead, and is actually part of the trail.
Now: Go do it with a fly!
(This article appeared in the May/June, 2018 issue of Northwest Fly Fishing magazine. If you’re interested in learning more about mountain lake fishing in Montana, you might consider my new book, Flyfisher’s Guide to Northwest Montana’s Mountain Lakes. The book is also available from Wilderness Adventures Press, Amazon, and Google Play)