Henry's Fork Fishing Report - September 18, 2025

Henry’s Fork Streamflows

Island Park Dam:  354 cfs

Ashton Dam:  1000 cfs

St. Anthony:  948 cfs

Fall River:  344 cfs

The Henry’s Fork has been waking up from its summertime slumber here this past week, with decent to good fishing opportunities throughout the system.  With reduced flows in the upper river, tributary and spring inputs are doing a great job of diluting the turbid water being released from Island Park Dam, and the river has good clarity through most of the fishing reaches.  Low flows but fishy conditions prevail at the moment. 

Box Canyon

Though the water coming right from the outlet at the dam is off color, the Buffalo River is doing a fine job of making the river fishable just below.  Low flows make for a bumpy ride in here, but the trout are biting and fishing is good.  Nymphs and streamers make up the bulk of the favored riggings, small nymphs and streamers of all sorts, dead drifted or stripped can be effective.  It’s weedy in there, so be sure to keep your flies clean.  A bag of B split shot will come in handy in the deeper runs and in others the weight of your flies will be sufficient, so be prepared to adjust to the water you’re fishing.  For nymphs, we are liking:  PTs, Rednecks, Cocktail Nymphs, HP Caddis Pupa, red and brown Zebra Midges, Juju Baetis #16-20, Rubberlegs #10-12.  Perdigons are always useful in here, we like red Jig Napoleons, Olive Hot Spots, Black Daggers, and any other favorites you might have in #16-18.  For streamers, it’s hard to beat a black/olive BFE or BSA Bouface, a Copper Zonker, olive/white two tone streamer or even a good old fashioned wooly bugger.

Railroad Ranch

Ranch anglers will find it worth their while to get out in the mornings in search of some rising trout.  The water is plenty clear and fishable at present.  This time of year has all sizes of trout eating dry flies, so careful observation will be a good skill to put to use when determining the size of the target.  Mahogany duns will drive the larger trout to the surface, with baetis and tricos keeping some of them interested in between.  Caddis are sparse but present.  Flies we like for this time of year are:  a variety of spinners in #16-22, Sparkle Flag Duns, Bucky’s Baetis #16-20, and a variety of Mahoganies:  Thorax Dun, CDC Biot Dun, Captive Duns, naked PTs, and soft hackle Mahoganies are among our favorites.  Cloudy and partly cloudy days will produce the most extended fishing hours and targets, while sunny days can still be productive in the morning and late morning hours. 

Canyon Country

The canyons have been fun places to be lately, with low flows and clear water, we are finding bitey trout throughout.  Dry/dropper rigs and streamers are producing the most action.  The Chubberlegs rig is hard to beat, a high viz dry fly on top and a BSA jig rubberlegs below, occasionally swapping out for a fast-sinking perdigon or beadhead nymph #14-16.  For streamers, a black or black/olive BFE, or black BSA Bouface will do the trick.  For a few more bites, try dropping a red Copper John off the back.  A floating line will keep you out of the rocks, leave the sink tips at home!  This time of year the weather can turn quickly, so be sure to bring plenty of layers and rain gear just in case!

Warm River to Ashton

This section continues to pump out good days of trout fishing on dry/dropper, indicator, and streamer rigs.  The diversity of water types in here lends itself to all of these rigs, and is a good place to experiment with sink tips when plying the larger runs with streamers.  Generally, the action is on smaller to medium-sized trout, but this is a great time of year to find a few larger surprises in between.  Fly selections should mirror those recommended for the Box Canyon.

Below Ashton Reservoir

The lower river is in play, cloudy days will be more interesting than sunny ones, but anglers can expect to find decent action on dry/dropper rigs and streamers.  Rising trout can be found for anglers who are looking for them.  Pseudos, baetis, small caddis and mahoganies are present in sparse numbers on sunny days and increasing numbers on cloudy ones.  The river is weedy down here, but not as bad as it has been in recent years.

Get out there and enjoy it while you can!!