Montana Fly Fishing 6 min read

DIY Guide to Fly Fishing the Beaverhead River in Montana

Ken Sperry

Posted by Ken Sperry

March 3, 2017

Beaverhead River Montana

The Beaverhead River produces more large brown trout than any other river in the state of Montana. This river runs for approximately 70 miles and is a tributary of the Jefferson River.

Traveling through the southwestern and central quadrant of the state, the Beaverhead provides fly fishing anglers with an opportunity of a lifetime. This river is not limited to browns, as rainbow trout call this home as well.

Yet this waterway offers it challenges. With its twists and turns and the heavy fishing pressure, the trout are finicky. Presentations must be accurate and well thought out. Yet the challenges that it presents do not come without rewards, as this river is a haven for trophy-sized browns. The scenery is pleasant with willows lining the riverbanks.

Beaverhead River Fishing Map

Map of fishing access spots on the Beaverhead River in Montana

Get Directions to the Fishing Access Points shown above with the DIY Fly Fishing Map

Floating the Beaverhead River: Clark Canyon Dam to Barretts Dam

There are two distinct sections of this river that offer the greatest fishing opportunities. First off we have the Clark Canyon Dam (below Clark Canyon Reservoir) to Barretts Dam, the section that receives the highest fishing pressure. It is a commonplace observation of anglers to view this section as a floaters highway. While the browns are heavily populated in this section, the fishing pressure coupled with the twisting nature of the river make for a challenging fly fishing experience.

Wade Fishing the Beaverhead River: Barretts Dam to Dillion

Then we have the Barretts Diversion Dam to Dillon, which covers 14 miles. Fishing pressure on this section is not as heavy. Will you find a place for solitude on this section? Doubtful, yet the floaters are typically not found on this section due to low water conditions. This is a waders paradise since the pressure is significantly less, thereby enabling the angler to go after less finicky trout.

Yet the Barretts Diversion Dam to Dillon does pose its own set of challenges. Access is limited with private land in abundance. Floaters have difficulty with the frequent low water conditions, especially during the summer months. For the angler who dislikes with a passion the trials that come with heavy fishing pressure, and prefers to wade if at all possible, this is your section. With what it lacks in access points it makes up for in the large brown trout population, as it is equal to the Clark Canyon Dam to Barretts Dam.

Large Brown Trout are the name of the game on the Beaverhead River. Video by Four Rivers Fishing Company.

Over this 14 mile stretch between Barretts Diversion Dam to Dillon, river access is limited. Are you willing to wade a short distance to have some sense of solitude? If so, this is your section. With the access points limited, all it takes is a short walk up or downstream to find an area of the river with light fishing pressure. Don’t forget our rattlesnake friends as they like to call this area home.

With irrigation withdrawals from Barretts Diversion Dam, low water is commonly found on this section. Hence the lighter floater traffic. A slower current paired with shallower water sets up the wade angler for excellent conditions. While floating is still possible pending water levels, wade fishing is the predominant choice.

Best Time to Fish the Beaverhead River

The summer months of June, July, and August offer anglers a variety of hatches and fishing opportunities. While the Beaverhead River can be fished all year, these summer months present several hatches, which in turn means abundant fly fishing opportunities.

While the Beaverhead River is best known as a Brown Trout fishery, it also contains some bruiser Rainbow Trout. Video by Four Rivers Fishing Company.

Beaverhead River Hatches

During the summer months the Beaverhead sees 3 particular hatches; those being PMDs, Yellow Sallies, and Caddis. Close to June 20th sees the PMD hatch begin followed closely by the Yellow Sallies and various Caddis species. If you are debating between the three summer months, July seems to be the height of the summer hatch season.

If you prefer some dry fly fishing, the month of August sees Tricos and the exciting Crane Flies making their descent on the water. The dry fly fishing that occurs during these Crane Flies events is known to get the heart’s pumping of even the most seasoned fly fishermen!

Of importance to note is that the variations in hatches across the river vary slightly, as with any other river. What may surprise some is the cannibal like attitude of the trout in this river. They are known to attack all types of living creatures from mice, the occasional snake and smaller fish. Speaking of snakes, it bears to be reminded again. For the wade anglers, be cognizant of the snakes.

Beaverhead River Fly Fishing Tips

If dry fly fishing is your forte, the Barretts Diversion Dam to Dillon offers a friendly body of water in comparison to upstream. With a prominent caddis hatch that occurs as the evening cools, the Elk Hair Caddis brings great results. Another option for the dry fly angler is to float attractor patterns right along the bank, in particular whenever there is an obstruction.

The following tips and tactics work well in both sections that have been mentioned previously. While our focus is on the less pressured Barretts Diversion Dam to Dillon, these tactics can be implemented to good results on the section from Clark Canyon Dam to Barretts Dam.

Dry Fly Fishing Tips

Going back to our dry fly approach, for those who prefer fishing on top, early mornings and late into the evening will see the best results with dry flies. If the weather has the sun out with few clouds on the horizon, the trout will not feed on top as they go deep. It is when there is cloud cover that the trout feed on top, especially with cooler temperatures. Popular patterns for the action up top are sizes 16-18 of Elk Hair Caddis, Sparkle Dun and the X-Caddis.

Backwater dry fly fishing is available, as the Beaverhead holds numerous backwater fishing spots. Hoppers are frequently used on the Beaverhead during the late summer months.

Nymphs and Streamers for Trophy Fish

The majority of the trophy sized fish taken on the Beaverhead River come with the use of nymphs and streamers. Precision is paramount as is the ability to dead drift the nymphs along the bank. While the current on the Barretts Diversion Dam to Dillon section is slower, it still requires consistent line mending. Light tippets will be required which ultimately lends itself to lost fish from time to time. Popular nymph patterns include sizes 10-16 of Hares Ear, Little Beaverhead Stone and Bead Head Pheasant Tail.

The consensus of fly fishing anglers that are experienced with this river is that nymphs are a necessity to take in trophy sized trout. Fish the nymphs into deeper holes and right along the bank for your best chances.

Gear Recommendations

A 9-foot 5-wt fly rod with floating line is perfect for fishing dry flies and small nymphs on the Beaverhead River. For larger nymphs and streamers a 9-foot 6-wt with a sink tip fly line makes life easier. A tapered 9-foot leader, with tippet size 3X to 6X to match the flies you are throwing, is pretty standard.

Beaverhead River Fishing Reports

There are a number of area fly shops that publish Beaverhead River fishing reports.  A few to check out are listed below.  Stop in to the get the latest conditions and pick up some flies.

Beaverhead River Flows and USGS Gauges

It is important to know that the flow of the Beaverhead River is controlled by the Clark Canyon Reservoir. Before you head out to fish, if you plan on floating, it would be wise to check the status of the river. Wade fishing, in particular on the Barretts Diversion Dam to Dillon section, should not be too adversely affected by the reservoir activity as the river typically runs shallow in this section.

If you do decide to float the upper section that receives the highest pressure, that being from Clark Canyon Dam to Barretts Dam, it is imperative to check the cfs flows. This also applies to wade fishing, as higher cfs flows can make for dangerous, if not impossible wade fishing conditions.

Clark Canyon Reservoir pool height, inflow and outflow conditions are available on the Montana Bureau of Reclamation website.

The USGS maintains stream gauges at Barretts, Dillion and Twin Bridges, MT.  Real-time stream flow data for the past 7-days at each of these locations is shown below and available via the DIY Fly Fishing App.


Beaverhead River Fishing Regulations

Montana Fish, Wildlife, and Parks has an easy to use website to secure your Nonresident license. The options that are available are for a 2-day fishing, 10-day fishing, and a season fishing license.

Please respect the private landowners as you access the Beaverhead River. Be sure to check the latest regulations and Beaverhead River Recreation Rules.

How to Get to the Beaverhead River

This river runs conveniently close to I-15 and I-90. If you will be flying into this region, your most affordable airfare will typically come by flying into Billings Logan International Airport, which is a 4 hour drive to Dillon. There are several other airports located closer, in particular Bozeman, yet the rates should be best flying into Billings.

This of course requires a rental car, and you will find the drive in to be scenic and well worth the short 4 hours to arrive at your destination. The city of Dillon has a nice selection of hotels, and camping is available throughout the Beaverhead River.

Visit our DIY Guide to Montana’s Best Fly Fishing for information on other fly fishing destinations in Montana.

Feature Image by Backcountry Angler