Big Hole River is hands down the best fly fishing destination in Montana. You’ll find five species of game fish here, including brown trout, rainbow trout, cutthroat trout, brook trout and fluvial arctic grayling. Most people come here for the plentiful population of large, wild rainbow and brown trout. There are strict fishing regulations at Big Hole River that help ensure the quality and quantity of fish remain at top levels. You can easily access the river for most of its length. You’ll find several informal road access sites as well as designated fishing access sites. These will allow you to access the shores so you can enjoy the excellent fishing Big Hole River has to offer.
The Big Hole River is made up of several distinct sections. Each section offers a unique habitat and fishing experience.
Big hole river headwaters extend to the North Fork. This section of the river is located at a higher elevation than the rest of the river and is perfect for anglers looking to dry fly-fish for brook trout, rainbow trout, and the native cutthroat and grayling. The upper portion of this section of the Big hole river is great for dry fly fishing for smaller trout.
Upper Big Hole
This section of the river extends from the North Fork to Dewey. It has a greater volume of water than the headwaters, is floatable, where you’ll find larger fish and brown trout. This expanse of the Big Hole remains cold in the summer months due to mountain stream flows that feed into it.
The Middle Canyon section of Big Hole River extends from Dewey to Salmon Fly (Melrose). Here Big Hole has small rapids rapids and pools, and the water conditions change around every bend. Some of the heavier hatches can be found in this section of the river, and it has a large concentration of trout (up to 3000 per mile). The Middle Canyon can get crowded when the salmon fly hatch begins in the spring.
Lower Big Hole
The Lower Big Hole section expands from Melrose to is confluence with Beaverhead. Once Melrose combines with Beaverhead near Twin Bridges, Big Hole River forms the Jefferson River. This section of the river is less crowded than the others. Trout concentration here are slightly lower than in the upper sections of the river. In the summer, get here early in the morning when the waters are cooler. During heat waves, there may be a curfew that all fishing must be completed before 2:00 p.m.
Knowing when to fish Big Hole river is almost as important as knowing where to fish it. There are four fishing seasons you should pay attention to for best fishing results.
Pre-runoff runs from mid April through May. During the pre-runoff, anglers come to Big Hole River to chase hatches and hunt big fish with streamers. Spring hatches get heavy when the baetis mayflies, Mother’s Day caddis and the skwala stoneflies start spawning. This is one of the best times of the year to fish the Big Hole if you like low pressure as angler typically don’t start arriving in masses until later.
The runoff begins where the pre-runoff ends in May and extends and lasts till the end of June. A three-week period of salmon-fly hatches occur during June, drawing hungry fish to the surface (and anglers to the river.) Smaller golden stoneflies hatches keep the fishing activity high even as salmon-fly hatches subside.
Summer fishing on Big Hole begins in July and ends in September. During the summer season hatches are in full force. Golden stone fly hatches continue as Pale Morning Dun (PMD) mayfly and Yellow Sally Stonefly hatches pick up up speed. Caddis and nocturnal stonefly hatches are present and should be fished in the morning when it’s still cool. You can also catch nice size trout using ants, spruce moths and grass hoppers.
Summer turns into fall during the month of September and runs up to the beginning of November. Many Big Hole anglers prefer the fall season, when water temperatures are cooler, and the river is less congested. The brown trout become more aggressive at this time.
Unfortunately, Big Hole is not good for winter fishing, as the river often completely freezes.