Henrys Fork
Henrys Fork in Island Park, Idaho is a famous dry fly river with big wild rainbows and wary browns, from Mack's Inn to Box Canyon and Harriman State Park.
- 180 miRiver length
- 6Game fish
- 64Access points
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About the Henrys Fork
Henrys Fork starts near Island Park in eastern Idaho and runs toward the Teton Valley and the Snake River plain. Anglers around Island Park, Ashton and Last Chance know it as one of the best dry fly rivers in the country. The river is long, but most of the famous water sits in the first few miles below Island Park Dam.
The upper river near Mack's Inn and Coffee Pot Rapids is faster and more forgiving. Below Island Park Dam you reach Box Canyon, a rugged run of pocket water that holds big rainbows. Downstream, the river slows and spreads out near Last Chance and Harriman State Park, where it turns into flat, clear, spring creek style water.
The Henrys Fork holds brown trout, rainbow trout, brook trout, Yellowstone cutthroat, mountain whitefish and cutbows. The rainbows are wild and strong. The browns are known for being picky about the drift.
The hatch list is long. Salmonflies and golden stones show up in early summer. Green drakes, pale morning duns, tricos and mahogany duns bring the technical dry fly fishing. Hoppers take over late in the season. Skwala stoneflies and blue-winged olives add early and late options.
Most people wade the flats and the canyon. Floating is common in other reaches. Harriman State Park has its own rules and the ranch water can have season dates, so check current Idaho regulations and park notices before you go.
Henrys Fork near Ashton, ID
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Nearby gages
- Teton River near St. Anthony, ID18.7 mi away Not reporting USGS 13055000
- North Fork Teton River near Sugar City, ID23.9 mi away Not reporting USGS 13055250
- Snake River at Lorenzo, ID36.0 mi away Not reporting USGS 13038500
- Camas Creek at Camas, ID36.8 mi away Not reporting USGS 13112000
- Snake River near Menan, ID37.7 mi away Not reporting USGS 13057000
- Madison River near West Yellowstone, MT39.4 mi away Not reporting USGS 06037500
- Snake River near Heise, ID40.5 mi away Not reporting USGS 13037500
- Snake River above Jackson Lake at Flagg Ranch, WY43.1 mi away Not reporting USGS 13010065
No gages that close. Try a wider radius.
See every gage on the map and today's top 10 rivers in the free appData from the U.S. Geological Survey. Recent readings are provisional and may be revised.
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Tips for fishing the Henrys Fork
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Start with the section, not the fly
The upper river, Box Canyon and the Harriman flats all fish very differently. Pick the water that matches your skill and your patience before you pick a fly.
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Give the flats a slow, careful approach
The slow water near Last Chance and the ranch is clear and the fish see everything. Stay low, move slowly and make long, drag free drifts.
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Fish Box Canyon with a sturdy staff
Box Canyon is fast and rocky. A wading staff and good boots matter more here than any fly choice.
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Plan around the big hatches
Salmonflies and golden stones come early in summer. Green drakes and pale morning duns follow. Ask a shop in Island Park or Last Chance what stage the hatches are in.
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Respect park hours and closures
Harriman State Park has its own hours and entry rules. Some water has a delayed opening in spring, so check before you drive out.
Every access point on the Henrys Fork, in your pocket.
- 64 mapped access points, with parking and put-ins
- Today's Fishability score, so you fish the day that lines up
- 7-day flow and water-temp trends for every gauge on the river
Rivers near the Henrys Fork
Henrys Fork FAQ
What is the best time to fish the Henrys Fork in Idaho?
Late spring through summer is the classic window for dry fly fishing. Salmonflies show up first, then green drakes and pale morning duns, and hoppers finish the season. Fall brings blue-winged olives and fewer people.
Where is the best place to fish the Henrys Fork?
Most anglers focus on three areas. Mack's Inn and Coffee Pot Rapids upstream, Box Canyon below Island Park Dam, and the flat water near Last Chance and Harriman State Park. The Warm River and Teton River are nearby if you want a change.
Can you wade the Henrys Fork?
Yes. The flats near Last Chance and the ranch are popular wade water, and Box Canyon can be waded with care. Floating is also common on other stretches.
What flies work on the Henrys Fork?
Classic dry flies carry the river. Think Elk Hair Caddis, Parachute Adams, pale morning dun patterns, green drake imitations, and hopper patterns late in summer. Golden stone and salmonfly patterns matter in early summer. The FlyFishFinder app shows what is hatching and working today.
What fish are in the Henrys Fork?
Brown trout, rainbow trout, brook trout, Yellowstone cutthroat, mountain whitefish and cutbows all live in the river. The rainbows and browns get most of the attention.
Are there special rules on the Henrys Fork?
Yes, the rules vary by reach and Harriman State Park has its own access rules. Check the current Idaho Fish and Game regulations and park notices before you fish.
