Henry's Fork Fishing Report - August 14, 2025

Henry’s Fork Streamflows

Island Park Dam:  730 cfs

Ashton Dam:  1540 cfs

St. Anthony:  948 cfs

Fall River:  267 cfs

Turbidity is present throughout the river on a highly variable basis.  For information regarding turbidity, check the Henry’s Fork Foundation’s River Conditions page.  Click on the “Water Quality” link, then select the monitoring station you’d like to view, selecting “turbidity” at the top of the chart for recent and current conditions.  The Foundation is working diligently to understand the complexities of the current situation, but at its core, this is a difficult water year and with a reservoir at 39%, there’s not much clear water upstream to work with.  Stay tuned for updates on current and future projects addressing this issue, the good folks at the Foundation are working hard to consider and develop long term solutions to this issue.

It’s a variable world out there in Henry’s Fork country, anglers wishing to ply the Fork’s waters will do well to check conditions the morning of before making their final decision as to where their adventures will take them.  The source of the issue is Island Park Reservoir, so the higher up in the system you’re fishing, changes can happen more quickly.  These turbidity events are working their way downriver, checking the HFF website along the course of the river can help you plan your day.  These events can be compared to a plug of mud on Montana’s Yellowstone River, you can literally watch it move through the system and time your endeavors ahead or behind.  Flows, oxygen levels and temperatures are still in good shape, but high turbidity must be watched for and avoided.  Anything over 6 NTUs is worth consideration of an alternative plan.

Serious dry fly anglers will do well to explore other areas in Yellowstone Country as there are plenty of opportunities around.  Nymph, dry/dropper, and streamer anglers can find interesting sections of river and plenty of fun fishing if they keep an eye on river conditions and plan accordingly.

Box Canyon

Though there can be some great fishing to be had in the Box Canyon during these times, anglers will have little warning when turbidity events come through the dam, so float it at your own risk!  Plenty of good opportunity when clarity is fair, the river usually becomes fishable a few hundred yards below the Buffalo River’s confluence if it’s a bit dirty up top.  During moments of less clarity, anglers should consider fishing darker flies, flies with hot spots, or other uses of fluorescents.  Streamers can be effective when clarity is off, it can have the same effect as low light conditions, and should not be overlooked.  We’re coming to the end of Golden Stones, but there may be a few around here and there, so a dry/dropper becomes more of a useful tool for nymphing shallow water rather than a rig that holds hope for a dry fly take.  Indicator nymphing rigs, as ever, will produce the most consistent results.  We like the following flies:  PTs, R/L Tactical PTs, Split Case PMDs, red and brown Zebra Midges and Rednecks #14-18, black Zebra Midges #18-20, HP Caddis Pupa and Hare/Copper SH #14-18, Rubberlegs #8-12 and SJWs #12-14.  For streamers, we like olive, black, white BFEs and BSA Boufaces in #4-10, and Olive/White two tone streamers like Galloup’s Barely Legal or Double Bunnies.

Railroad Ranch

As much as I’d like to spread the good word and put some hope out there, conditions have not been favorable for Ranch anglers.  The most dedicated are finding a few rising trout here and there, and the setting makes for a terrific place to take your fly rod for a walk.  However, if your expectation is to find good numbers of quality rising trout, you might consider a shift in your plan for the day.  Insects are present in fair numbers and can provide some game on any given day, so for those venturing into these fabled waters, don’t be without a variety of spinners #14-22 in a range of colors(don't forget tricos and callibaetis), flying ant imitations, grasshoppers, some caddis and PMDs in all forms.  More stable conditions will be found in areas with spring influence, the more the better!  Patterns we like are:  Halfback PMDs, Klinkhammer PMDs, as well as LC Cripples and CDC Biot Dun PMDs to cover emergent and knockdowns, both Heames and Harrops Honey Ants, Shimazaki Ants #14-20, and a handful of hopper patterns, especially a Moorish hopper or two #6-10.  Dark HF Caddis #16-18 and plenty of spinners will round it out.

Canyon Country

Generally speaking, these sections are providing consistent fishing for a variety of sizes of trout.  These are terrific sections to spend a summer’s day floating and fishing.  Flows are excellent for both navigation and for reading the water.  It’s rare that you’ll find a crowd or a bad day while fishing these sections.  We generally are fishing dry/dropper rigs, a “Chubby/Rubby” or “Chubberlegs” is an ideal combination:  a high visibility Chubby Chernobyl with a Rubberlegs stonefly nymph underneath.  Streamers have their place and are a great way to cover a variety of water with a single fly as well as to target larger trout.  It’s hard to beat a black or olive BFE, BSA Bouface, a copper Zonker or olive/white two-tone streamer in here.  As always, remember a raft and solid oarsmanship is the price of entry into these sections.

Warm River to Ashton

Though the occasional turbidity event can reach even this most consistent piece of water, we are generally having fun days down here with good to decent action on smaller trout.  There are a few larger surprises here and there, and successes can be found with just about any rig you can dream up:  Dry flies, dry/droppers, and streamers all have their place in this beautiful section of river.  Fly selections can mirror those recommended for the Box Canyon.  As we enter the middle of August, remember that brown trout are now beginning to think about their annual sojourn to their spawning grounds, they become not only more deeply colored but more territorial as well.  Streamer fishing opportunities can be explored with a variety of lines in here, the water is suitable for both floating and sink tip lines.

Below Ashton Dam

The lower river is a few weeks away from being a reliable fishery but longer and cooler nights are already beginning to change the water temperature.  More opportunities will be had in the morning and evening hours, but cooler days will have some midday opportunity.  Streamers and hoppers will provide some action, and occasionally a dropper or deep nymph will find a fish as well. 

Get out and enjoy these summer days while we have them!