Henrys Fork Fly Fishing

One of the most diverse and beautiful flyfishing rivers in the Western United States, located one half hour’s drive from West Yellowstone to the North and one hour from Idaho Falls to the south.

In these pages we will give you a comprehensive overview of the entire river system, where to go and what to use-, access and tips on what’s hot and what’s not-, fishing reports, the latest news, and connections for tackle, car rental and other reservations.

We also visit some other streams in the immediate area.

Sections of the River

The Henry’s Fork of the Snake River

120 miles of river from it’s origin in Henry’s Lake until it joins the main Snake river.

Below you will find a general description of the entire river.

The Henry’s Fork averages about 3000 trout per mile in the middle section, the Box Canyon and the Railroad ranch area, and has one of the best growth rates of any river.

The river originates in Henry’ Lake, famous for it’s large cruising trout, leaves the lake as the “Outlet” and meanders through the pastoral surrounding of Henry’s Lake Flat all the while joined by many smaller creeks and springs and slowly growing in volume. At the end of the flat, the river enters a swampy and brushy area before it is joined by the waters of Big Springs outlet which triples the river’s size. At the juncture the river turns west again.

Past Mack’s Inn resort the river, still traveling west, enters a shallow canyon and becomes a mountain stream with riffles, glides, pools and deep runs, ending in the Coffee Pot rapids. Here the river turns south again through a short deep canyon. (Sometimes inadvertently called Cardiac Canyon). After leaving the canyon there is a slower stretch until the river passes McCrea Bridge and flows into Island Park Reservoir.

At the dam of the reservoir, the Buffalo Fork river joins up and the combined river disappears into Box Canyon. Box Canyon is only 2 1/2 miles long but offers some of the best fast water fishing on the river. The river leaves the Box Canyon at the resorts of Box Canyon and Henry’ Fork villages and enters a slower stretch with nice deep runs and moderately deep water.

Railroad Ranch

Around the bend is Last Change. Here we have what is called the Last Change run, a 2 mile stretch of of splendid water, before the river enters Harriman State Park, also known as the Railroad Ranch. An abundance of cover and aquatic insects makes this 5 mile stretch of river a prolific aquarium of well fed trout,- easy on the trout but not the fishermen (and women).

The last 1 1/2 miles of water leading down to the Osborne Bridge is a little easier to fish for most. but the fish tend to be smaller.

Once the river crosses Highway 191 it curves in big bends and is smooth and easily wadeable. 2 miles downstream from the Osborne Bridge the river passes through a little enclave called Pine Haven. The water here is a well weeded, medium deep channel run.

After Pine Haven, the river becomes more boulder strewn and faster. At Riverside, another 2 miles downstream the river really flows until it reaches Sheep Falls, 7 miles further downstream.

After Sheep Falls the river enters Cardiac Canyon, passes over the Upper- and Lower Mesa Falls and 12 miles below reaches Warm River .

At the confluence with the Warm River, the volume doubles and the river turns into a large flatland stream which curves along the edge of the Island Park plateau and runs into Ashton Reservoir. Below Ashton Reservoir the river is much cooler again and holds good sized trout for a couple of miles.

The best and most famous part of the river you will find above Sheep Creek Falls. Thereafter the quality of fishing gradually deteriorates because of difficult access, with of course, the usual exceptions in local areas.


The Henry’s Fork river from Pinehaven through Cardiac Canyon to the confluence with the Warm River.

The canyon is aptly named. It requires good physical condition and lots of courage to wade and in some cases, to get down into the canyon from the rim. The fish are there but access is limited to a few places.

From Pinehaven to Sheep Falls is sometimes floated. Take out is at Hatchery Ford, above the falls. For wading anglers there are some logging roads which lead to the river from the Mesa Falls scenic drive. One usually can fish up and down stream from where any of the roads come in.The river above the falls is fast and rocky. There is good pocket water fishing with big stonefly nymphs and streamers. Large attractors work sometimes well. Below Hatchery Ford road access is only possible via an old road off highway 20, south of the Riverside campground. The road leads to Mesa Falls. (see map).

From Sheep Falls to Upper Mesa Falls is 4 miles of fast and sometimes violent water. Access to the river is very difficult. The nearest road is highway 47 at Upper and Lower Mesa Falls. (see map) Like the stretch above Sheep Falls and the stretch below the lower Falls, this is not fished much. Only during the salmon fly hatch does one see many anglers. Although the river looks menacing, fish in the 10-17 inch range are abundant. Fish only from shore if you decide to hike in and give it a try. Watch for rising water levels because of unpredictable dam releases!

The canyon below the Lower Mesa Falls is called Bear Gulch. Although the canyon is everywhere close to the Mesa Falls Scenic drive, there is only one dirt road, – near Grandview campground -, which leads to the canyon rim. The river is still 1/2 a mile below. For those few who float this stretch, that is the launch ramp. The river has big rocks, rapids and minor falls. Fishing on dries can be very good for smaller trout. Larger fish will only go for nymphs and streamers.

Box Canyon

From Island Park Dam to 1 mile before Last Change.

Many years ago the Idaho Fish and Game Department stopped stocking the river below Island Park reservoir. The river from here on down nowadays contains only wild trout.

Many dirt road leading from highway 20 into the woods, give access to this stretch of water. As before, too many roads can be misleading and get you lost.

Fast water, riffles, pools and deep runs. Some of the best fast water fishing anywhere.

The river below Island Park reservoir is subject to sometimes severe water level fluctuations because of dam releases. These water releases are mostly unpredictable and can make for quick changes in wadeability as far down as Sheep Creek Falls.

Island Park Reservoir
Although the current is fast, the boulder strewn bottom provides thousands of good holding spots throughout the canyon. Because of the abundance of aquatic insects,- many stonefly species amongst all others-, the fish grow big and strong. Find a good holding spot and the fish are there.

The water below the dam and the next 3/4 miles to the junction with the Buffalo river, is not as fast as further down the canyon and wading is much easier. The dam outlet has created a deep hole, with big rocks and big fish. The gravel bar below provides good nymphing and sometimes dry fly actions on both sides. The rapids above the Buffalo river junction hold good fish also and so does the fast chute below it. After the Box Canyon campground, the river slows a bit into a grassy bank area called “the Meadows”. Large attractors can be effective here. At low water, much of this flat stretch can be waded.

After the river bends left, you’ll find some rapids and deep runs. An experienced and careful wader can fish this stretch well with nymphs or streamers. A few hundred yard below here is the Falls access road. This area and the rest of the river downstream have lots of good holding areas for big trout. There is one more access road before the first cabins near the end of the canyon. In between this road and the first cabins is a good run which can yield big fish. At the first cabins this run turns into rapids which plunge into a deep hole. Here the canyon opens up and the river flattens. Use large attractors, hoppers , trudes or caddis for some good dry fly fishing.

As a general rule, if you are not floating the river, picking a spot to fish the Box below the Buffalo river, can be a random act. The fish are there, and not one area is much better then the other for the fish, but it can be for the angler. Some spots are harder on the fisherman then others. Choose whatever you prefer.

Floating the river gives access to the entire stream and is preferred by many. For many years, fishing from a boat or raft was not allowed. Although regulations have changed, stopping and wading selective spots and thereby covering the water more thoroughly, is still by far the best way to fish this particular water.

This shows the stretch of the river coming out of the “Box” and into the Last Change run, through Harriman State Park (Railroad Ranch), then onto the Osborne Bridge and the river just past Riverside, ending 5 miles before Sheep Creek Falls.

This central area of the Henry’s Fork river is the most famous of all. The upper ranch is still a continuation of Last Change run but further into the ranch water the erstwhile rubble bottom of the Last Chance run changes into silt and gravel with weed beds and deeper holes. Slow water, sophisticated fish, prolific hatches, – of which the Green Drake hatch is the best known- , require great fishing skill. Long leaders, pin-point casting, stealth, lots of patience and a good understanding of insect life forms is a necessity.

Aquatic food sources abundant, often different hatches occur at the same time with fish feeding on different insect or insect forms, requiring you to determine which fly to try first.

Still best known as the “Railroad Ranch” but since 1977 officially called ” Harriman State Park”, after the original owners who donated this treasure to ensure continued protection of this unique area, not only for fishing but also as a bird refuge. The ranch is a prime breeding area for the endangered Trumpeter Swan. This is also the reason the ranch waters are closed to fishing until the end of June, to give the swans time to finish their breeding. Harriman State Park stretches beyond Osborne bridge, but the “ranch” properly, ends 1/2 a mile above this bridge.

Most fishing is done by casting to rising trout and often a downstream presentation is required to avoid lining the fish. These fish are highly educated and refuse anything with drag or bad presentation. Although the surface looks slow and glassy, particularly in the mid ranch sections, underwater structures, weed beds and holes cause strange and often unseen currents which make a drag free presentation very difficult. Micro drag is your worst enemy here.

Immediately after the ranch bridge, you’ll find even deeper holes which are not wadeable and of course, hold large fish.

Hereafter the river narrows and speeds up. After the bend the river splits around some islands and turns into a long riffle and run which continues to Osborne bridge. About 1/2 a mile up from the bridge on the south side of the river is a large parking lot and the main entrance to the Park. This is a pleasant stretch to fish and does not receive much fishing pressure. The trout tend to be smaller.

At Last Chance, you’ll find some of the long established and best known fly shops and guide services for this river. It pays to visit and get the latest information on where to go and what to fish. Or better, have a guide show you the best ways to fish this demanding water. It might be one of the better investments of your trip.

After the bridge the river slowly changes in appearance. The first 3 miles below the bridge is still a continuation of the river immediately above but with more riffles and glides and occasionally deeper runs. The long bends create shallower areas and the river is very wadeable. Access to this entire stretch is from the Mesa Falls Scenic Drive which turns of highway 20 a 1/2 mile north of the bridge. This is in fact the old highway. Many dirt roads and ruts turn off the Scenic drive back towards the river. Some of these have signs, most do not, but all give you access to various parts of this stretch of river. Other access (to the west bank of the river) is from the main highway to Riverside campground and to Riverside and Pinehaven itself

The river above and below Pinehaven is choice water. Deeper runs, weed beds and larger fish. Below Pinehaven the river speeds up more. Between Pinehaven and Riverside is fast but varied water, -good runs, glides, pocket water and few fishermen. Fine water for nymphs and large attractors.

The Henry’s Fork from Warm River to St. Anthony

After the confluence with the Warm River, the Henry’s Fork continues westward, still in a canyon but not as severe as the previous one. A gravel road leads along the north side of the river until it joins highway 191/20. On the south side you can reach the river via an old railroad right away.

River below Warm River
Most of the fishing below Warm River is done by floating. For many guide services the stretch from here to Ashton reservoir is a daily routine.Some parts here are wadeable.

In this stretch brown trout are becoming more abundant. The river has becomes wider and slower and riffles, runs and deeper holes hold good numbers of sizeable fish. Nymphing is still the most productive way to fish the river here, although attractor flies cast towards the banks can have good results. Here the adagio, big flies for big fish, holds true. The larger nymphs produce best.

Some dry fly caddis action can be had in the evening, particularly in the wadeable stretches above the highway bridge. Where the river enters Ashton reservoir, near the float pull out, some good evening fishing for cruising trout can be had.

The river below the reservoir is considerably cooler because of cold water dam releases. Again, as on the previous stretch, most of the fishing is from boats because of private property along both banks. To reach the river, take the road straight west out of Ashton. After crossing the river there is a dirt road leading along the river for a short distance. After the parking, a trail follows the river further south. Depending on reservoir releases, much of this part is wadeable and dry fly fishing can be good. If you do not float the river, this is a good spot to fish.

River below Ashton
The river downstream has deep runs and occasional channels. Most fish are in the channels, unless feeding on the surface in the shallows. Caddis hatches occur daily. The gray drake hatch in June creates good surface activity by larger trout also.

At Vernon Bridge wade anglers have good access again. Both above and below the bridge you’ll find good,- and wadeable-, areas.
Seeley Backwaters

Further down river, near the Seeley Ranch take-out, are the backwaters. Too deep to wade, but well fished from a kick boat or raft. These waters are well known for their large cruising trout which rise whenever there is a hatch on. These fish spook easily and are difficult to approach. Down and across with a lot of slack is the best way to reach them. If no fish are rising, nymphs can be effective in the channels among the weed beds. This is also where the Falls River joins the Henry’s Fork. The area right above the dam can be reaches by taking the road west at Chesters.

Below the Chester dam is wadeable water and some good riffles which have plenty of small trout. Again, the best and sometimes only access is by floating. Some drop-offs, deeper runs and channels along small islands make this good holding water for numerous trout.

River at St.Anthony
The river below St. Antony again flows through mostly private property. Irrigation demands put a heavy strain on the river and the many irrigation canals are a yearly cause of fish kill when at the end of the summer, the canals dry up. The river is very much a delta-type stream, braided, with channels and islands. There are still good trout numbers, although coarse fish are getting the upper hand. Below the junction with the Teton River, the river gets warmer and the water quality less. Trout have practically disappeared when the Henry’s Fork joins the Snake near Menan Buttes.


Hatch Chart

Period Dates Sizes Insect
April-May Spring #18 Iron Blue Quill
May-June 5/1-6/25 #4-6 Salmon fly
June 30-May #6-8 Golden Stone fly
June 20-30 #8-10 Green Drake
June 30-Oct #16-18 Pale Morning Dun
June-July months #10-18 Caddis
June-July 6/20-7/5 #10-12 Brown Drake
June-July 6/20-7/31 #20-22 Small Blue Quill
July 28-Jan #14-16 Small Western Drake
July 20-Oct #12 Light Cahill
July-August Months #8-10 Gray Drake
July-August 7/15-8/31 #18-20 Pale Morning Dun
July-August Months #14-16 Speckled Spinner
July-August Months #22-24 Small Blue Wing Olive
August 31-Jan #20-22 White Wing Black
August-September Months #22-24 Small Blue Wing Olive
September 30-Jan #16-18 Mahogany Dun
September-October Months #22-24 Small Blue Wing Olive
October 15-30 #12-14 Snowflake Dun
October-November Fall #18 Iron Blue Quill

Nearby Streams

Warm River

The Warm river is an attractive spring creek. It originates in Warm Springs (See photo) at the site of an old hatchery. From thereon it travels south nearly parallel to the Henry’s Fork river through a 7 mile long wild canyon until it joins the Henry’s Fork below Bear Gulch Canyon. It is a major tributary of the Henry’s Fork.

The railroad to W.Yellowstone runs along the river for most of its length. Not many people fish this excellent stream above the Pineview siding were a small road (Hatchery Butte road) comes to the river, off the the Mesa Falls Drive. Many smaller roads crisscross the area but most are hard to find while travelling around since none of them are marked. The maps show you most of these “ruts”. A 4-wheel drive vehicle is advised.

Up from the confluence with the Henry’s Fork, before the campground, Robinson Creek enters the Warm River. A beautiful little stream for small dry flies and attractors. The fish are small. Its tributary, Fish Creek, is also good for pan sized fish. A gravel road gives access for about three miles to this area. Another access is from above, using the Mesa Falls Drive.

Falls River

The Fall River originates in the S.W. corner of Yellowstone Park and travel Southwesterly until it joins the Henry’s Fork near Chester Backwaters. One of its headwaters is the Bechler River. Before it leaves the Park, you’ll find Cave Falls. A road leads from Ashton to the Cave Falls campground. Reclamation road, off highway 32, parallels the river for a couple of miles also. From highway 32, which crosses the river between Ashton and Drummond, there is about 60 miles of river to the Cave Falls campground.

You’ll find mostly rainbows and browns in the lower stretch, with cutthroats in the upper. Most of the time the river is a little discolored. Three river crossing give good access to parts of the stream.

Other areas, where no road parallels the river, are more difficult to access because of private property rights. All and along the steam is private property. The river is not much fished by any standard, with may be the exception in the upper part near the campground and the confluence with the Bechler River.

Much of the river is riffle and runs over boulder gravel bottom. Most standard flies and nymphs will do fine. The upper reaches have stone flies.

How to Get There

Both West Yellowstone to the north and Idaho Falls to the south have a commercial airport. Both are served by Delta airlines and/or one of its affiliated carriers.

Each city is approximately a one hour’s drive from the central river area (Last Change).

Road distances:
Idaho Falls – Island Park 71 miles
Island Park – West Yellowstone: 81 miles.