Henry's Fork Fishing Report - August 6, 2026

Henry’s Fork Streamflows

Island Park Dam:  996 cfs

Ashton Dam:  1600 cfs

St. Anthony:  1090 cfs

Fall River:  314 cfs

As we round the corner into the final stretch of summer, the Henry’s Fork continues to have better conditions than originally forecated for this time of year.  Flows remain stable at just under 1000 cfs out of Island Park Dam, turbidity has been kept to an acceptable measure, water temperatures are holding throughout the upper river, dissolved oxygen levels remain solid, and fishing has been fair to good where it should be in the upper river.  Another warm and dry week ahead of us, but now with longer and progressively cooler nights working with us to combat rising water temperatures and keep things in the acceptable range. 

Box Canyon

The Box has been fishing well overall with good action on nymphs, there are still a few golden stoneflies around to generate some interest in the occasional surface eat.  Things are starting to get weedy in here, so be sure to check your flies for bits of weeds if a hookset comes up empty.  Indicator nymph rigs are the most productive and reliable at the moment, B shot and a variety of sizes of beadheads will cover you in most water.  We currently like the following:  PTs, Hare/Coppers, Rednecks, Frenchies, red and brown Zebra Midges, Cocktail Nymphs, HP Caddis Pupa #14-18, Rubberlegs #10, claret SJWs #10-12.  For perdigons we like the Black Dagger, Olive Hot Spot, red Jig Napoleon, Spanish Bullet, Bullet Quill #14-18.  Flows remain comfortable in here, making the Box a good option for either a full day or a half-day’s float.

Railroad Ranch

The Ranch has had sparse hatches and even sparser rising trout, but there are a few around here and there for the dedicated angler that wants to hunt large trout in challenging conditions.  In exchange for challenging conditions and limited opportunities, solitude can easily be found on the Ranch, which also makes for an enjoyable experience.  If anglers can keep their expectations of opportunities in check, some very nice days can be had down here, and some very large trout are around to be taken, occasionally.  For hatches, we’re seeing sparse caddis #16-18, a few flav spinners #14, PMD spinners #14-16, some callibaetis spinners #14, and decent numbers of a variety of smaller spinners #20-22 at times.  PMDs are hatching in the afternoons where springs are present in small numbers on sunny days and slightly increasing numbers during cloudy afternoons.  Anglers will do well to keep a variety of terrestrials on hand, including grasshoppers, small black ants, and honey ants, these all can provide opportunity on any given day. 

Canyon Country

The canyons are fishing well and we expect them to keep doing so for the foreseeable future, lots of oxygen down there and limited hours of exposure to the sun keep water temps cool and trout happy down here.  This is stonefly habitat from top to bottom, a dry/dropper rig with that in mind will serve you well and if the trout are being fussy, change the rubberlegs dropper out for a Rosa Pink or Blowtorch #12-14 to change your luck.  Small and medium sized fish are the average catch down here, but the canyons are capable of producing big surprises, so be ready for it when it happens!

Warm River to Ashton

This section of river continues to produce quality days of fishing and floating fun with good action on smaller and medium sized trout.  Like the canyons above, this section has plenty of larger trout that will show themselves from time to time.  While indicator nymphing rigs are the standard down here, a dry/dropper with a rubberlegs below or streamer rig can be useful when trying to target a few larger trout.  Fly selections should be about the same as those recommended for the Box Canyon.  Morning hours are primarily utilized by anglers, but be mindful of your backcast when the splash and giggle crowd shows up in the afternoons! 

Below Ashton Reservoir

Warm days and relatively high water temps in the lower river keep most fishing windows and opportunities down here pretty limited at the moment.  Anglers will generally do well to focus their efforts upstream for the time being. 

Good luck out there!!