Idaho Fishing Reports ยท Upper Snake Region
Box Canyon is the fast, rocky three miles of the Henrys Fork below Island Park Dam, known for big rainbows that hold in heavy pocket water.
Looking for the latest Henrys Fork (Box Canyon) river report? This page is updated by the AvidMax fly shop team with live flows, current conditions, hatches and the flies working now on the Henrys Fork (Box Canyon).
Current flows
Wind forecast
Henrys Fork fishing report
Updated November 7, 2026.
Winter releases from Island Park Dam are low, so the canyon is easier to wade than in summer.
Nymph the deeper slots with stonefly and small mayfly nymphs, and watch for BWOs on cloudy afternoons.
Load your fly box
Before you head to Box Canyon, bring: Pat', s Rubber Legs #6-10, Pheasant Tail Nymph #14-18, Zebra Midge #18-22, JuJu Baetis #18-20, Parachute Adams #16-20, Woolly Bugger #6-8, RS2 Emerger #18-22, Black Beauty #20-24, Egg #14-16, Squirmy Wormie #12-14.
Flies working right now
The flies above that we have in stock right now.
Henrys Fork details
| Access | Walk in from Box Canyon Campground and the Last Chance side, or float from below the dam to Last Chance. |
|---|---|
| Elevation | About 6,200 ft |
| Nearest town | Island Park, Idaho |
| Best season | Year-round, best late spring through fall |
| Fish | Wild rainbow trout |
| Regulations | Catch-and-release rules apply on parts of the upper Henrys Fork. Check the Idaho Department of Fish and Game seasons and rules before you go. An Idaho fishing license is required for anglers 14 and older, plus a steelhead or salmon permit where those fish are targeted. |
| Leaders and tippet | 9 ft leaders, 3X to 5X tippet |
| Camping | Box Canyon Campground (Caribou-Targhee National Forest) |
| Kids | No. Fast, slippery water. |
| Good to know | The rocks are very slick. Wear studs and use a wading staff. |
Fishing by season
Winter
Midges and nymphing on low flows.
Spring
BWOs and stoneflies.
Summer
Salmonflies and golden stones in June, then caddis.
Fall
BWOs and streamers.
How to get there
From Ashton, take US-20 north to Island Park and follow signs to Box Canyon Campground.