Henry's Fork Fishing Report - September 25, 2025

Henry’s Fork Streamflows

Island Park Dam:  340 cfs

Ashton Dam:  990 cfs

St. Anthony:  936 cfs

Fall River:  450 cfs

Greetings, Henry’s Fork aficionados!

Steve Hoovler here, stepping in for Jonathan this week while he’s off chasing silver salmon and giant rainbows in the wilds of Alaska. I’ll do my best to fill his well-worn wading boots and bring you a solid look at what’s happening across the Henry’s Fork.

Jonathan will be back next week with his thoughtful and nuanced take on the fishery—but in the meantime, I’m happy to walk you through the current conditions, key hatches, and what we’re seeing on the water during this beautiful stretch of early fall.

Box Canyon

Flows are still low through the box, but turbidity continues to drop making for some good dry-dropper and nymph fishing for those willing to navigate the basalt boulders on foot or floating. 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 are finding more and more opportunity these days as water clarity continues to improve, and Mahogany Dun mayflies trickle off in the late mornings and early afternoons. Cool, cloudy days next week may provide a good chance to see more concentrated numbers of mayflies, and large heads up. As is usually the case this time of year, there are a lot of small fish rising in the Ranch, and it's important to take some time to evaluate your targets and search for the good ones. 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.  

Canyon Country

It's still hard to find a prettier place to spend an autumn day on a wilderness float. Water clarity is great, and fish are still responding well to dry-dropper rigs and streamers fished on a floating line. 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.

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.