The Missouri River is formed with the confluence of the Jefferson, Madison, and Gallatin rivers near Three Forks, Montana. The blue-ribbon stretches of the river are generally considered downstream in the “tail-water” sections, which are formed below several reservoirs. The best trout fishing section of the Missouri River is the stretch of river downstream from Holter Lake that our guides fish in the spring and early summer. Closer to Bozeman is the stretch of the Missouri River around Toston Reservoir which is a great mid-summer Carp destination that also holds a few large trout seasonally.
As a true tail-water fishery, the Missouri River is rich in biomass of aquatic invertebrates but lacks the diversity of species typically found in the freestone rivers closer to Bozeman. Prolific hatches of Mayflies in all but the coldest months of the year attracts anglers from around the world. Caddis and terrestrials bring fish to the surface throughout the summer months. It is a dry fly fisherman’s paradise!
When to Fly Fish the Missouri River
The Missouri River is a year round wild trout river that can fish exceptionally well anytime of the year. We are always willing to head up to the Missouri for a few days of fishing with our guests that want to give it a try. There are a few times of year when it’s not the best choice, so we avoid going up there when conditions are not ideal. Our favorite time of year is May and June on the Missouri as there are less people around, there are no weeds in the river, and warming water temperatures keep the fish feeding all throughout the day.
Rainbows spawn in March and April, typically make a mass exodus from the main river into a handful of smaller streams during this time of year. This is about the only time of year we avoid the river, but there are still plenty of fish that remain in the main river and fishing can be quite good, especially on cloudy days.
Late summer gets hot and the water temperature of the Missouri River is significantly affected by the long, hot days of late July and August. Water temperatures typically reach the upper 60’s and cool very little overnight. Trout feed less during this time of year and for shorter periods of time throughout the day. Good numbers can still be found, but it usually requires more work than the rest of the year. Add to that the mass of aquatic vegetation that seems to cover the entire river surface and bottom during this time year and just getting a clean fly to a feeding fish is the biggest part of the problem. Recreational floaters flock to the Missouri as well to enjoy the beauty and refreshing waters this time year, so it can be quite crowded.
The Fish We Catch
Rainbow Trout are the more common species that we tend to see most days on the Missouri River, but Brown Trout are also regular visitors to the nets of our guides. As a wild trout fishery, there is a wide range of different sized trout that are always present in the river. Unlike most of the rivers we fish in the state, the stretch of the Missouri, just below Holter Dam has a good number of hatchery-raised Rainbows that have come over the dam during times of increased flows. Overall though, the Missouri has some of the highest wild trout densities in the state and tend to average around 17” from year to year. Most of the fish we catch and see throughout the year will be smaller than 20”, but there is always a handful of Browns reaching 24” that find our guides' nets as well. Larger fish are present in the river for sure and a dedicated streamer angler can occasionally find a fish in the 25-30 inch range.
Carp fishing has gained in popularity the last few years and the upper Missouri River offers some of the best fly fishing for Carp around. Fish typically are in the 4-8 pound range - so not as big as some other place - but they are prolific to say the least. Notoriously difficult to catch, fishing this area is unique in that anglers can expect to get dozens and
