Henry's Fork Fishing Report - August 27, 2026

Henry’s Fork Streamflows

Island Park Dam:  693 cfs

Ashton Dam:  1290 cfs

St. Anthony:  1130 cfs

Fall River:  344 cfs

The Henry’s Fork has been fishing well lately and some promising change in the weather department has us hopeful that it will improve over this week.  Stormy weather in the next few days will likely be wet and cloudy and make things interesting throughout the system.  This is a significant amount of rain, so anglers should keep an eye on the Henry’s Fork Foundation’s water quality website and keep a finger on the pulse of turbidity out of Island Park dam, as this could stir things up a bit. 

Box Canyon

The Box has been fishing well and should respond favorably to the forecast, but anglers will definitely want to keep an eye on that turbidity situation.  At the moment, the water coming out of the west side of the dam is pretty dirty, but the east side remains clear enough to keep it fishable.  The east side has the bulk of the flow at the moment, so that’s the one to watch.  Flows remain comfortable for a streamer run or an all day nymphing affair, structure is easily read at this level.  Weeds are an issue that must be dealt with, coming into the canyon with the expectation of having to tend to your flies will help temper your frustration here.  These trout won’t touch a fly with weeds on it, so take the time to keep things clean.  Fishing with less weight will help in this regard.  Indicator nymph rigs are the most common producer here, but during the storm cycle streamers can be an effective choice as well.  For fly selection, we’re liking the following:  PTs, red and brown Zebra Midges, Split Case PMDs, Rednecks #14-18 and Rubberlegs stonefly nymphs and SJWs #10-12.  Many perdigons will work but we especially like Olive Hot Spots, Spanish Bullets, Jakes’ SH, Black Daggers and red Jig Napoleons #16-18 this time of year.  For streamers, we generally like black and olive or a combination of the two, but a copper Zonker is an old time favorite as well.  Try a BFE or BSA Bouface to get things started.

Railroad Ranch

The Ranch has been on a long and slow trend of improvement over the past weeks when it comes to fishing.  There are good targets out there for those who are willing to cover ground looking for them, but there haven’t been high numbers.  Anglers looking for solitude and a chance at a trophy rainbow trout can be pleased in here.  With the coming forecast, we’re expecting a shift in insect activity that should lead to a few more targets, keep an eye out for Mahogany duns and Baetis activity during the storm cycle.  During the warmer spells, calllibaetis and flying ants have been driving the bite for larger trout, so anglers will want to be prepared for all of these.  We would make sure we have the following:  Harrop’s Paraspinner and Hackle Stacker Callibaetis, Harrop’s and Heames’ Honey Ants, Shimazaki Black Ant, a range of small spinners like Paraspinners and Copenhaver spinners, CDC thorax Mahogany, CDC Biot Dun Mahogany and Quigley’s Flag Dun baetis. 

Canyon Country

The canyons of the Henry’s Fork have been fishing well all summer and will likely continue to do so through September.  These are great sections to be in on sunny days, but anglers won’t want to be down here on stormy ones unless they are well prepared with layers and quality rain gear.  Dry/dropper rigs are still the way to go down here, but streamers will play for those inclined to look for larger but fewer trout.  Solid oarsmanship and an inflatable raft are a must.

Warm River to Ashton

This section holds promise for anglers of all skill levels; indicator nymphing rigs can be used from ramp to ramp with solid results, streamers can be used in a hunt for larger trout, and dry flies can be successful during periods of warm weather.  It’s a bit of “choose your own adventure” down here and this is a fun section to be in for a day’s work of mixing it up.  Brown trout are beginning to get territorial prior to their annual spawning migrations and are beginning to move around in the system, which always makes for some large trout potential for anglers who are willing to look for them.  For flies, one needn’t stray too far from the Box Canyon recommendations, be sure to add in some hopper patterns for the dry fly situation.

Below Ashon Dam

The lower river has been pretty quiet lately, barring a few short windows of opportunity.  This will begin to change with the weather, but it’s easy to jump the gun down here and expect too much too soon.  Though stormy weather can help produce good results down here, it’ll take a few cycles and lower water temperatures to really get things going in these sections.  Keep an eye on the weather and choose your forays carefully.  Subsurface fishing will dominate the fishing day, but there will be terrestrial potential here and there when the sun comes out. 

Good luck out there!!