February 19th, 2007

The Big Horn River
By Neil M. Travis, Montana

"This is a good sized, but very muddy stream that provides very little fishing at this time, except in the 'after bay' for about 300 yards just below the Yellowtail dam. In this area it is fair for rainbow and brown trout, plus some sauger and catfish. As a result of the dam the next 10 or 15 miles downstream are rapidly improving and should be good fishing in the near future." That was the description given to the Bighorn River in The Montanans' Fishing Guide by Dick Konizeski, printed in 1970 by Mountain Press Publishing Company, in Missoula, MT. Ernie Schwiebert's magnum opus Trout , published in 1978 by Button, does not even mention the Bighorn! In fact, no mention of the Bighorn River can be found in any angling book until the mid-'80s.

When the first settlers arrived in Montana territory the Bighorn River was a large prairie river, flowing in a generally northerly fashion out of the Bighorn Mountains, until it entered the Yellowstone River. Most Americans are familiar with a tributary of the Bighorn, Greasy Grass Creek, the name given to the Little Bighorn by the Native Americans.

The Bighorn River has its headwaters far to the South in Wyoming, in the Wind River Range of the Rocky Mountains. It flows out through the Wind River Indian Reservation and is aptly called the Wind River. At Thermopolis, Wyoming the river receives a new name, the Bighorn. The river continues its journey north across Wyoming cutting its way through a canyon into Montana. In the late '50s work began on a dam which would impound the waters of the Bighorn River near the mouth of Bighorn Canyon on the Montana/Wyoming border. Yellowtail dam was completed in 1965 and transformed the downstream section of the Bighorn River into a world class tailwater trout fishery. For many years only a few fortunate anglers were able to fish the upper area of the river due to a dispute between the Crow tribe and the State of Montana over who owned the riverbed. In the mid-'80s the United States Supreme Court ruled for the State of Montana and the river became open to the general public. Today, from a base at Fort Smith, the only town near the dam, anglers can access the prime fishing water of the Bighorn River.

The Stream

The Bighorn River in Montana is a typical low gradient prairie stream. What has transformed the Bighorn River from a warm, sluggish, muddy stream meandering across the plains into a world class trout fishery is the Yellowtail Dam. Constructed to generate hydroelectric power, the Yellowtail Dam is a bottom spill-type. The Bighorn Canyon is deep and the resulting impoundment captures the entire flow of the river forming a lake that extends back into Wyoming. The colder water sinks to the bottom of the reservoir and is released below the dam. The resulting flow is not only cold, but rich in nutrients... ideal for trout and the food that they require.

After the water leaves the dam it flows through a short section of canyon and then into a small lake created by a low dam. This area is called the Afterbay. The dam, reservoir and Afterbay are controlled by the Federal Government, and managed as the Bighorn Canyon National Recreational Area with headquarters at Fort Smith, Montana. From the Afterbay downstream, the next 13 miles is some of the finest classic tailwater trout fishing to be found in the world. Due to the consistency of the flow, both in volume and temperature, the stream has a spring creek-like quality. Nutrients released with the water from the bottom of the reservoir create an ideal habitat for plant growth and extensive beds of weed carpet the bottom. The weed beds offer excellent habitat for the prolific hatches that characterize the Bighorn fishery.

The Bighorn is a large river. Below Afterbay, where the fishery begins, the river is over 100 feet wide and six to eight feet deep. The river drops gradually so there are few riffles and no white water. The river is characterized by long flats, deep pools, and back channels behind islands. Many of the favorite spots have descriptive names like Red Cliffs, Glory Hole, Aquarium, and Rainbow Run.


The Bighorn River flows through a desolate part of south-central Montana, with very few roads to afford access to the river. Adding to the access problem is the fact that most of the upper river runs through the Crow Indian Reservation, limiting access to pieces of land owned by the state or individuals. The only town near the upper river is Fort Smith which is located at the end of Highway 313. The nearest large town is Hardin, Montana, approximately 55 miles from Fort Smith. Billings, Montana, which is about 90 miles from Fort Smith, is the nearest city with an airport that handles jet planes. There is a small airstrip just east of Fort Smith that can handle small private planes.

Fort Smith offers limited overnight accommodations, restaurant, gas station and several tackle shops. Camping is available at a campground run by the federal government at Afterbay, and a private campground near 3 mile access. Some of the outfitting services offer lodging, meals, and transportation.

The Fishery

The river is predominately a brown trout fishery. Rainbows have been completely protected since the river opened to the public and their numbers are increasing, but brown trout still make up the bulk of the population. Due to the cold water temperatures in the late winter and early spring, rainbow spawning is delayed. It is not uncommon to find rainbows spawning into May, long after you would find them spawning on rivers like the Yellowstone or the Madison.

Fishing the Bighorn

For the angler who has never fished in the West, or the angler who has never fished the Bighorn before, a few words of advice are appropriate at this juncture. Most visiting anglers come to fish the Bighorn during the summer months. On the eastern plains of Montana, the daytime temperatures during July and August routinely exceed 90 degrees. While the river is very cold, the sun will quickly turn any exposed skin into the color of a freshly boiled lobster. Sun screen, hats with brims, Polaroid sun glasses, and long sleeved shirts are the order of the day. For the angler who comes in the spring and fall, warm and cold weather clothing is a must. Weather changes quickly in this part of the world and a warm sunny day in April or May can just as quickly turn into a cold miserable one, with bone chilling rain or wet snow. The same is true in September and October. Take it from one who has been there. A few moments preparation and planning can mean the difference between an enjoyable day and a miserable experience. It's a long way between take-outs when you're sitting in a Mackenzie boat with nothing but a cotton shirt between you and a cold rain being driven upstream by a north wind! Much has been written about the Bighorn and the resulting publicity has had its prescribed effect. Do not come to the Bighorn if you are looking for solitude. Except during the months of mid-winter, it is likely that you will be sharing the river with many fellow anglers. While the river is large and there are numerous places to fish, crowding in some of the more popular areas is a reality and the visiting angler should come prepared for that.

Fort Smith offers the angler several fly shops and outfitting services that cater to all of the needs of the most demanding fly fisher. Due to its size and lack of access, the most rewarding way to fish the Bighorn is by floating. Those coming to fish the Bighorn for the first time would be well advised to hire one of the many excellent local guides. They will supply the boat, lunch and, most importantly, the expertise necessary to make your trip enjoyable.

The Bighorn is open to angling year-round, however, cold water temperatures during the winter months and the unpredictable weather make winter angling a risky proposition. Many of the local businesses close during the winter or operate on very reduced schedules, making angling during these periods a more difficult proposition.

When to Come

As noted above, the Bighorn River is open to year-round angling, and depending upon your angling preference you can catch fish on the river anytime of the year.

During the months of November, December, January, and February, weather is the limiting factor. Practically speaking, the upper Bighorn is a long way from the nearest major town, and while that is somewhat of a blessing, it makes the river difficult to fish during times of uncertain weather. It's just a long way to travel to find out that the weather has made the fishing difficult, if not impossible. For the angler who wishes to fish the Bighorn during these months, the following suggestions should prove helpful.

Water temperatures are usually quite cold, averaging in the mid to upper 30s. The fishing will be slow, with nymphs and streamers the order of the day. Weather may change frequently and strong winds are very common. The days are short this far north in the winter so the angler's time on the water will be limited. Fort Smith does not offer much in the way of night life, so visiting anglers should bring several good books. Accommodations in Fort Smith are limited so anglers who intend to stay near the river should check ahead before they come.

In March things begin to happen on the Bighorn. Weather continues to be a factor, but there are usually more fishable days as daylight increases with the coming of spring. Water temperatures will still be in the 30s and fishing will continue to be mostly with nymphs and streamers. Midges and blue-winged olives are usually hatching, and occasionally in the late afternoon some fish may be taken on dry flies during this period, however, that is the exception rather than the rule.

April and May normally comprise the two best months of spring fishing. Despite the fact that the river is controlled by a dam, water levels do fluctuate depending upon the amount of snowpack in the mountains. In April and May they are usually filling the dam and water levels will be low, and any increase in the flow will generally be gradual. During these two months midges and blue-winged olives hatch in untold numbers, and along the banks and below riffle tailouts, the trout will gather in pods to feed on the emerging insects. For the angler who lives for the thrill of fishing to large trout with small flies, this is angler's Valhalla. However, even Eden had a serpent, and with the increased hatches comes increased angler numbers, and with the increased pressure the fish can become extremely spooky. These months offer extremely rewarding but challenging angling.

June is a transition month on the Bighorn. The prolific midge and blue-winged olive hatches have begun to wane and no other major hatch has replaced them. If the snow pack was heavy, water levels may be high during June and early July. Nymphs, fished deep, will be the most productive. For the angler who prefers dry fly angling, the pickings are usually slim, but terrestrials like beetles, ants, and attractor patterns will produce a few fish for the persistent angler.

Late July, August, and September are super-hatch months on the Bighorn. Water temperatures will warm into the low 50s and the fish are quite active. By this time of year the water levels have usually stabilized.

Although the flows may be high, if they remain stable it does not affect the fishing. By mid-July the pale morning dun hatch begins and continues to build into the month of August.

August and September are truly dry fly months on the Bighorn. Pale morning duns, tricos, and caddis are available in August. In September the pale morning duns are replaced by fall baetis and pseudocleons. These months also marks the peak of angler numbers and anglers need to check their egos and tempers before they get on the stream.

October is the transition month, both in the weather and the fishing. Like the spring months, the angler can have some great dry fly fishing. Trico fishing may continue until mid-month and in some years continue into November. Fall baetis, pseudocleons, tan caddis, and midges round out the trout's diet. Scuds and San Juan Worms can keep the nymph fishing angler busy.

What to Bring

The Bighorn is a big river flowing through a vast, high plains environment. Due to the nature of the land, wind is a common phenomenon, especially in the afternoon. Rods capable of delivering a fly into the wind are a necessity, as are the skills necessary to cast under such conditions. Since most anglers will be floating the river it is easy to carry more than one rod. This will allow the angler to cover a variety of angling situations. Most of the angling will be with relatively small flies or weighted nymphs, therefore rods that can handle line weights in the 4 to 6 weight range are more than ample. For dry fly fishing when the wind is not blowing or in sheltered areas, many anglers prefer rods in the 2 to 3 weight line class. I have personally had some excellent fishing using a 1 weight rod.

Neoprene waders are the best type of wader to use on the Bighorn due to the cold water temperature. Unless the angler only intends to fish from the boat, chest high waders are the wader of choice. Even with Neoprene waders it is preferable to wear some type of thermal underwear and heavy socks inside the waders. Standing waist deep in 40 degree water for long periods of time will chill all but the most hot blooded angler.

Rain gear is a must when fishing the Bighorn during the warmer months of the year. Late afternoon thundershowers are common and they usually occur just when the fishing is starting to get exciting. Hats with long bills reduce the glare, and hats that provide some form of protection for the neck and ears are especially helpful. Polaroid glasses, sun screen and lip balm round out the personal hygiene items.

Depending on the time of year and the type of fishing one expects to encounter, the type of flies the angler will need varies. Midges are available most of the year, and scuds and sowbugs are always present. Beyond that the angler should come with well stocked fly boxes containing a variety of different patterns. The visiting angler should take advantage of the information available from the local fly shops and be prepared to purchase or tie up some of the "hot" patterns.

The Experience

To quote Roderick Haig-Brown, "Sometimes the least important thing about the fishing, is fishing." While the Bighorn is truly a world class fishery, anyone who only comes to spend their every waking moment fishing is missing much of what the river has to offer. The setting of the river is truly spectacular. Cutting its way across the plains it flows through a vast open country. The river bottom is rich and covered with groves of cottonwoods. The understory is a mixture of shrubs, grasses, and various non-woody plants. This makes a rich habitat for a myriad of birds and other small wildlife. Much of the surrounding land is high plains country, thus the river bottom provides a green oasis in the middle of an otherwise semi-arid environment. Wildlife is a mixture of Midwestern and Western species, both finding suitable habitat for their needs along the river. Waterfowl and assorted shorebirds flock to the river, especially in spring and fall. It should be noted that this is rattlesnake country, and anglers wandering around on the islands or along the banks should be watchful.

Overall the country is big and truly personifies the idea of "Big Sky Country," the name many people apply to Montana. A float down the Bighorn is a marvelous sensory experience, aside from the wonderful angling possibilities. So, while you're there take a break from the fishing, and enjoy the total experience of the place, its wildlife, its serenity, and its grandeur. Your trip, and your person, will be richer for the experience.


Hatch Chart

~ Neil M. Travis, Montana/Arizona

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