Henry's Fork Fishing Report - August 7, 2025

Henry’s Fork Streamflows

Island Park Dam:  839 cfs

Ashton Dam:  1540 cfs

St. Anthony:  936 cfs

Fall River:  262 cfs

The Henry’s Fork remains similar to as it has been these past two weeks, thanks to the diversity of this fabled trout stream good fishing opportunity remains in some of its reaches.  Dry fly purists will find persisting difficult conditions at this time, with a meagerly but steadily improving situation.  Anglers wishing to fish faster moving reaches of the river will find some great days of trout fishing.  Flows are in great shape through most of the system, water temperatures look generally great for the time of year, but clarity in the upper river is highly variable and NOT great.  Turbidity is at its highest right below Island Park Dam and improves with each mile traveled downstream.  Check the Henry’s Fork Foundation’s website for live updates on not only turbidity, but temperatures and dissolved oxygen levels throughout the watershed to stay up to date as well:  www.henrysfork.org

Box Canyon

Though the river can resemble a watery version of split pea soup directly beneath Island Park Dam, the addition of the Buffalo River just downstream improves clarity, especially as the water mixes in the miles downstream, the river is very fishable a few hundred yards below this confluence.  Not every day has equal clarity and better fishing will be found in the upstream sections during periods of higher visibility, smaller flies and more realistic imitations will prevail in these conditions.  In more turbid times, anglers will do well to consider larger flies and patterns with hot spots or other uses of fluorescents.  Flows are great for an all day affair or for a quicker run with minimal stopping.  Lots of fun fishing to be had in the Box this week for the indicator-nymphing crowd.  Dry/droppers and streamers will be fair choices as well.  There are still a few golden stones around, so an occasional dry fly taker isn’t out of the question, and there are lots of food items in the water presently that are best imitated by a streamer (think, rainbow fry, leeches, and whitefish fry).  Nymphs we wouldn’t be without are:  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

Not much to report on the Ranch these days other than to say that flows are nice, there are decent numbers of bugs around, and not too many trout eating on the surface.  There are periods of better activity, mornings and evenings will be better choices than midday, but anglers should be prepared to walk longer distances to find a small number of targets.  On a lighter note, they will also find solitude, something that is hard to find at this time of year and something that makes those scarce targets even more valuable and memorable.  There is plenty of joy to be found in taking your fly rod for a morning walk in the Ranch, and the potential to find something memorable is there every day for those who enter with proper expectations.

This year's water year ranks in the top ten of the worst water years in the last 100, there's not much water in the reservoir and we'll likely be fighting water quality for most of the rest of the season on the Ranch, which is generally the most sensitive section of the Fork. Tricos, Callibaetis, PMDs, Caddis, occasional Gray Drakes, flying ants and grasshoppers are all on the menu and present.  Anglers should plan on having a large variety of small spinners in several colors #14-20, a small selection of dark and tan caddis #16-20, 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 their favorite hopper patterns, especially a Moorish hopper or two #6-10. 

Canyon Country

The canyons of the Henry’s Fork are like their own universe at times like this;  good flows, less weedy conditions, and biting trout make for fun days in these whitewater wilderness sections of the river.  Canyon walls make for more hours in the shade on hot summer days, and can give more hours of streamer fishing conditions than found in other reaches of the river.  Dry/dropper rigs are our preferred choice down here, with most activity found on the dropper, but there are generally at least a few trout that will take a dry fly along the way.  Streamers can be a great choice in here for lower numbers of fish but a general increase in size.  We like fast-sinking streamers on long 8-9’ leaders with floating lines, line control is a must in these sections, there are rocks everywhere and lots of different currents to deal with.  Solid oarsmanship and a raft are a must, and a nice forecast shouldn’t be taken for granted, always pack rain gear when committing to these floats.

Warm River to Ashton

This is one of the most consistent reaches of the river when it comes to a fun day’s fishing.  Good flows, great water temps and hungry trout are usually served up down here.  Fishing opportunities here favor the angler seeking quantity over quality, but larger trout can be targeted down here with streamer patters and dry/dropper rigs.  Indicator rigs will provide anglers with the most activity and fly selections should be reflective of those recommended for the Box Canyon.

Below Ashton Dam

While there are a few opportunities in the wee hours, these sections are generally characterized by slower fishing at this time of year.  Some trout can be taken on streamers, grasshopper imitations and occasionally by nymphing rigs, but anglers will do best to focus their efforts before noon and later in the evenings.

Enjoy some summer fishing while we still have it!