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Beaverhead Trout

Beaverhead Trout

Montana's Beaverhead River seems too small to hold a lot of large trout and yet, somehow, it keeps trophy anglers thigh deep in big browns and 'bows.

Guide Cassandra Osborn tries her hand at a section of the Beaverhead where big trout would use moss along the far shore to escape.
Photo by Ray Rychnovsky

The big fish on my line was in the fast current running downriver and I was troubled. My fly line was gone and my backing was coming off my reel far too fast. I took a few steps downstream but it was only a gesture. With a rock-strewn river in front of me and a steep bank with no shore on which to sprint behind me, I had no hope of stopping the fleeing fish. Nothing stood between the fish and its use of the current to assist its escape. Suddenly it turned and swam upriver. WHEE! Now I had a chance. I cranked the single-action reel as fast as I could. The fish was moving faster than I was reeling but the force of the swift current kept tension in the line.

The fish passed in front of me as I backed to the water's edge. Things were looking up. If I could keep the fish in the slower water at the edge of the river I could land this Beaverhead River trout.

"This one's a big rainbow," guide Cassandra Osborn announced. I had just landed a 19-inch brown trout from this same spot that had fought the same way, sprinting downriver; then, on its own volition, turning upriver where we could net, photograph and release it. I couldn't believe I was that lucky on two successive fish.

Osborn got the net in position downriver from the fish then signaled me to ease up on my line and let the current sweep the fish into the net, the same strategy we'd used on the brown. The fish sensed the net and spurted ahead. Two times the fish avoided the net but the third time Osborn scooped up the rainbow, my size 20 PMD nymph hanging from its lip. She measured the fat fish and we both beamed -- 23 inches! What a great wild trout. We took a few quick photos and let it swim out of the net.


The Beaverhead River is in the heart of Southwest Montana, surrounded by about a half-dozen blue ribbon trout rivers and streams. The great fishing section of the Beaverhead runs from Clark Canyon Dam, where we were fishing, past the town of Dillon. The river continues to Twin Bridges, where it joins the Big Hole and the Ruby rivers to become the Jefferson River.

The Beaverhead is a small river noted for big trout. Big browns live throughout the river but big rainbows are an equal attraction below Clark Canyon Dam.


This is an historic sight, as well. Lewis and Clark camped at Beaverhead Rock on the bank of this river across the road from Five Rivers Lodge where I stayed. Part of their party made a trip with their famous lady Indian guide, Sacagawea to meet her Shoshone people on land that is now submerged under Clark Canyon Reservoir. They traded for horses and supplies for their trip west while others in the exploration party recuperated at Beaverhead Rock.


We started fishing the lower Beaverhead River below Dillon. My guide had access to private waters so we were fishing a sparsely fished area in the morning. We hooked brown trout here but moss in the river gave the big ones an escape routine that they had learned well -- as soon as they were hooked, they dove down under the moss, getting the leader tangled in the heavy vegetation and pulling free.

We were getting lots of takes and almost as many hookups but our landing ratio was low. I still landed a couple large browns and a whitefish. Osborn, who fished so that I could take photos, landed a very nice 19-inch brown. She managed to pull that one on top of the moss and I scooped up as much moss as fish when I netted it. We had hooked even larger fish that used the moss to escape.

"Two weeks ago when I fished here it was like popcorn popping as fish were coming up to take flies off the surface," Osborn said. "Insects were hatching, the river flow was higher and the moss was washed away. We were casting size 16 or 18 pale morning duns and small stimulator dry flies and catching fish on almost every cast."


The Beaverhead is a great fly-fishing river. Present a natural-looking imitation of an insect the fish are eating and it is an almost sure take. Large fish here eat small nymphs, leading to the success of size 18 to 20 flies.

I used a 9-foot, 5 weight G Loomis fly rod with a reel made by the same manufacturer. Whether you are using surface or subsurface flies, a floating fly line is all you need.

An indicator, a split shot and two flies make up the standard rig for fishing wet flies here. Set the indicator at twice the depth you are fishing. The indicator usually goes under on a take, but set the hook when you see any disturbance of this floating aid. Guide Cassandra Osborn uses two indicators, one white and one red. This lets her see whether what she is watching is the indicator or something else floating on the river's surface.

A 4X Fluorocarbon tippet -- nearly invisible underwater -- gives you an edge. These fish see a lot of flies in a season and any advantage helps.

Dry Flies are red hot at times, starting with size 14 to 18 Yellow Stimulator, Yellow Sallies or caddis flies in April and May; reduce by two sizes in June and July. Sometime in July or early August, grasshoppers start hitting the water. Match them with size 8 to 12 hopper patterns through September.

A pale morning dun emerger was the hot fly for the big fish below the dam when I was there, but patterns change. Check with a local fly shop for the best flies when you are going.

Silver or gold Mepps spinners and Panther Marlins, from ¼ to ½-ounce will catch fish. Use a spinning outilt, cast across the current and retrieve slowly as the lure is taken down river. -- Ray Rychnovsky



"Let's go upriver to the dam," Osborn said. "It's challenging fishing, but we have a chance to catch a very large brown or rainbow trout there." We drove across the dam of the Clark Canyon Reservoir 19 miles south of the town of Dillon and circled back to the river to a good public river access point. Several anglers were there, including one group starting a trip in a drift boat, but I wouldn't call it crowded. Osborn saw a large fish on the far side of a deep channel and could be approached better from the far shore. We marked its location relative to landmarks, walked downriver to a shallow area and waded to the other side. We couldn't see the fish from that angle but used our markers to find the right spot. I cast my flies to it without success then cast nymph

s to the general area for 40 minutes and still had no takes. I was wondering if we had made a good move.

We waded downriver to some faster water and Osborn had me cast into riffles coming off a boulder 15 feet from our position. I cast to the near side of the rock, in front of the rock and downstream from the rock without a take. I continued to cast, working the far side of the boulder then working farther into the river. Finally something solid was on my line, a fish going downriver fast, and I couldn't apply enough force to turn it. This 19-inch brown trout turned and swam back upriver just as my large rainbow would do later. I was a very lucky angler this day. I was sure this was going to be the highlight of my day but 15 minutes later the large 'bow took my fly.


"This river is very low running less than 200 cubic feet per second," Osborn said. "When farmers need water for irrigation, water releases from the dam may be as high as 1,000 cfs. They are cutting and baling hay (their primary crop) and they don't need water at this time so the water flow is minimal."

With low flow rates, we could wade below Clark Canyon Dam but with higher flows, water would be deep and flowing fast from bank to bank, making this area almost impossible to wade. A raft or drift boat could be used here but the lower section of the river after much of the water was diverted to irrigation would be running at a more normal level and good fishing continues.

Access is good from the dam north to Dillon with frequent spots to launch or retrieve a boat. Farther north, access is less frequent and you must make a very long drift or have access to private property to fish this area.

People can fish from a drift boat or raft and the river has good access for wading. When the river is low, shallow areas are a challenge to drifters. A raft can run these areas and has advantages over a conventional drift boat but both will work. Spots on the river are narrow so it seems like the oars of a boat would almost touch both banks. The person on the oars needs to be on top of his game to keep the boat in the channel and off the shoreline.

Drifting this river has some challenges. Some of the ramps are rough, making it difficult to launch or retrieve a boat. Sometimes irrigation diversion channels can funnel you off to a dangerous dam if you don't know which channel to take. If you are drifting on your own, make sure you know the right channel and walk all launch areas you plan to use to be sure you can manage your boat and vehicle at both your put-in and take-out sites.

This small river that you can easily throw a rock across has a history of holding at least one 4-pound trout every 25 feet on average, according to Norm Strung's book, Fishing the Headwaters of the Missouri, published in 1980. The number of large brown and rainbow trout here make this river a great place to hunt trophy trout.


Anglers can keep Beaverhead River trout, and they can fish with flies, lures or bait. You may keep only one trout larger than 18 inches long the entire length of the river. If you crave fresh trout, keep a modest sized fish for dinner and release the rest.

The daily and possession limit is three trout from Clark Canyon Dam down river to Anderson Lane about seven miles north of Dillion, but fishermen must release all rainbow trout.

Below Anderson Lane Bridge you may keep five trout, including one rainbow trout. You must release all cutthroat trout and grayling.

Be sure to check the regulations!

Fishing might be closed if the flows are too low and the water becomes too warm. Closures are unusual, but in dry years when flows are low check to be certain fishing is permitted. -- Ray Rychnovsky



I fished here the second week in July, but fishing is good all season. Early season fishing starts in April or May using Yellow Sally, Blue-Winged Olives and large caddis flies. June and July still has blue wing olives but pale morning dunes (the nymph of this insect was our hot fly) and smaller caddis flies are also hatching. By the end of July, grasshoppers are added and that mix continues to until cold weather drives anglers away in September or early October. Large wet flies like Bitch Creek flies, black or brown Woolly Buggers and Muddler Minnows can be good anytime during the season.


I stayed at Five Rivers Lodge and my guide was arranged through this facility. This is an excellent lodge in the heart of great fly-fishing country. In addition to this river, anglers fish the Big Hole, Jefferson, Ruby and Madison River.

With large rooms, great meals, a well-stocked tackle shop including the largest selection of flies I have ever seen, this is a great starting place to fish several rivers in this area. Owner Jay Burgin is very friendly and has contracts with perhaps the best guides in the area. While all their guides are good, I think Osborn is the best and will ask for her when I go back. Call them at (800) 378-5006 or visit online to get information and make reservations.

You can fish here on your own by staying in Dillon. It has several motels, including the Best Western Paradise Inn (406-683-4214) and Comfort Inn (406-683-6831). Fly-fishing shops that can arrange guides include Backcountry Anglers in Dillon, (406) 683-3462.

Historic sites in the area include the restored gold mining town of Bannack at Bannack State Park 25 miles west of Dillon. There you will find more than 60 historic buildings along its main street. Call (406) 834-3413 or visit the Web site for information.

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