Henry's Fork Report - September 19, 2024

Henry’s Fork Streamflows

Island Park Dam:  349 cfs

Ashton Dam:  1200 cfs

St. Anthony:  1430 cfs

Fall River:  817 cfs

The Henry’s Fork is typically a fine place to be in the final weeks of September and this year is no exception, good fishing can be found throughout its length for anglers seeking opportunity.  Fall fishing on the Fork is generally a mix of nymph fishing, streamer fishing, and dry fly fishing to rising trout, each technique will provide good results for anglers who understand how to strategize their fishing day and target the right water for their intended pursuit.  Keeping a close eye on the weather will help guide you to success, choose the right water and techniques for the day that mother nature provides you.  Flows are low river-wide, which is normal for the time of year, and turbidity is up due to the cold snap of weather that we’re currently experiencing, but generally fair and fishable from about a mile downstream of Island Park Dam.

Box Canyon

The Box is a bumpy endeavor at these flows, but fall fishing in the canyon is some of the best of the year for those anglers looking for good action on small, medium and some larger trout with nymphing rigs.  Dry/droppers will produce at these flows as well, but standard nymphing rigs are the most versatile.  Streamer runs are always a good idea for those so inclined, usually best on cloudy days or once the sunlight is off the water.  For nymphs, think midges, baetis and mahogany imitations in #16-20, with a few stoneflies mixed in.  We are liking the following flies in there:  PTs, Cocktail Nymphs, Juju Baetis, Micro Mays, red and brown Zebra Midges #16-20.  An assortment of perdigons is a staple in most anglers’ boxes these days, we like the following:  Jake’s SH, Olive Hot Spot, Frenchies, red Jig Napoleons, Firestarters, Spanish Bullets, and Bullet Quills #16-18.

Railroad Ranch

Good game is being found on the Ranch these days with good numbers of pseudos, baetis and some mahogany duns hatching out there.  Spinner falls are present most days, but the daily midday hatch is what will drive most of the fish to the surface.  Mahogany duns are the bug of choice when present, and baetis will bring all sizes of fish to the surface, on cloudy days the larger trout will play with small bugs as well.  Keep a keen eye out for spotty caddis hatches, too.  Now is a good time to come prepared with spinners, duns, emergers, and cripples of all the insects in play, fall trout like to rise, but they have a summer’s worth of smarts and wariness written into their memory banks and behavioral patterns.  Most dry fly angling will take place during 3 or 4 hours in the middle of the day, but on cold rainy days this activity may not start until 2pm.  Ideal time to be on the water is from 10am-4pm, anglers will typically find the best fishing of the day in that window.  Though it’s hard to imagine when the rain has been falling for two days and the daily high isn’t creeping above 40 degrees, terrestrials will still be present during afternoon spells of warmth, keep a few hoppers on hand for these moments.

Canyon Country

These sections offer some of the most scenic places on the Henry’s Fork at this time of year, the mountain alders and aspen are changing colors and the lower light angles of late fall are magical.  That said, the fishing window is getting shorter and you don’t want to be trapped in these canyons when the weather turns foul.  Keep a close eye on the forecast and bring extra layers regardless of what it says.  Streamer fishing and dry/dropper fishing will produce the most steady results at this time of year, but spotty areas with some dry fly fishing are a possibility and nymph rigs worked in some of the deeper runs will definitely produce results.

Warm River to Ashton

This is the workhorse section of the Henry’s Fork for beginner anglers and those who generally favor quantity over quality, but this time of year has plenty of quality trout potential for anglers willing to ply its waters in search of larger trout.  Generally, nymph rigs are the standard choice here, but streamers on floating lines and even sink tips are worth the effort.  Anglers who seek dry fly targets can find a few quality trout that are willing when the baetis are hatching heavily.  Strong skills of observation lead to these dividends, take a moment to survey the water any time you have good numbers of insects on the water and you just may find a surprise that other people aren’t noticing.

Below Ashton Reservoir

Fishing has been good down below, water temps are in good shape and the trout are back into a feeding rhythm.  Everything plays down here and anglers will do well to be prepared for a few different techniques during the course of the day.  Typically, we are nymph fishing or streamer fishing in the morning hours, hoping for some dry fly fishing to rising trout in the afternoons, and prepared to carry on with the subsurface game afterwards or in between dry fly targets.  Baetis are the bug most common down here, but sparse mahogany hatches will bring up the larger trout.  Pay close attention to rise forms, it can be difficult at this time of year to discern a quality trout from a smaller one. 

Get out there and have fun!