Updated October 15, 2026

    Henry's Fork of the Snake River

    river in Idaho

    The Henry's Fork is a diverse river offering everything from technical dry fly water at Harriman State Park to heavy pocket water in the Box Canyon.

    River flow last 30 days

    04008001,2001,600Sep 16Sep 22Sep 27183 cfs
    Flow now
    92cfs
    Below the typical range (173–188 cfs)
    Last 7 days
    Steady
    183 to 373 cfs
    Bite report · week of Oct 4

    Strong Blue-Winged Olive (BWO) hatches

    1. 01Strong Blue-Winged Olive (BWO) hatches, especially on overcast afternoons.
    2. 02Consistent Mahogany Dun and October Caddis activity providing dry fly opportunities.
    3. 03Midges and Speckled Spinners remain a year-round staple.
    4. 04Focus on slower, meandering sections, Harriman Ranch, and Ashton to Funny Farm stretch.
    5. 05Pay close attention to rise forms; use delicate dry flies/emergers for risers and dry-dropper rigs in faster water.

    Past reports week by week

    13 weeks

    What to tie on

    Picked from reports, hatches and the season. Tap a fly for the recipe and where else it works.

    nymph

    Zebra Midge

    Midge pupa (Chironomidae)
    #18#20#22#24

    Midges are a primary and consistent food source year-round, and this weighted pattern is highly effective for getting into the strike zone in colder fall water.

    Buy at Amazon
    nymph

    Flashback Pheasant Tail Nymph

    #14#16#18

    An excellent general searching nymph, mimicking various active mayfly nymphs that are present year-round, especially as BWOs emerge in the fall.

    dry

    Blue-Winged Olive (BWO) Comparadun

    Baetis (BWO) adult
    #18#20#22#24

    BWOs are actively hatching in the fall, and this low-profile dry fly is excellent for selective trout keying on emergers and adults.

    Buy at Amazon
    egg

    Blood Dot Egg

    Salmon/trout egg
    #10#12#14

    Fall is the egg season below spawning salmon and trout, making egg patterns highly effective for opportunistic feeders.

    Buy at Amazon
    dry

    October Caddis (Dry)

    October Caddis (Dicosmoecus) adult
    #6#8#10

    The October Caddis is the largest caddis hatch of the year in many western rivers, drawing aggressive strikes from trout looking for a substantial meal.

    Buy at Amazon
    dry

    Mahogany Dun

    Paraleptophlebia adult
    #14#16#18

    Mahogany Duns are actively hatching in late summer and fall, providing good dry fly opportunities.

    Buy at Amazon
    streamer

    Woolly Bugger (Olive)

    #4#6#8

    A versatile streamer effective for imitating leeches and baitfish, enticing aggressive strikes from larger trout in cooling fall waters.

    Where to fish and who to ask

    Henry's Fork Anglers · Last ChanceTroutHunter · Island ParkThree Rivers Ranch Outfitters · Ashton, Driggs, Island Park, BoiseMadison River Outfitters · West Yellowstone1Box Canyon Access2Last Chance Access3The Millionaire's Pool
    AccessFly shopGuide trips
    1

    Box Canyon Access

    The iconic entrance to the Island Park Reservoir reach, offering miles of wade fishing.

    44.409°N 111.400°WUSGS 13042500Directions
    2

    Last Chance Access

    A key access point for the lower river as it exits the caldera.

    44.305°N 111.516°WDirections
    3

    The Millionaire's Pool

    A legendary flat-water stretch within Harriman State Park.

    44.331°N 111.459°WDirections

    Fly shops within 40 miles

    4mi

    Henry's Fork Anglers

    Last Chance, IDGuide trips
    6mi

    TroutHunter

    Island Park, IDGuide trips
    22mi

    Three Rivers Ranch Outfitters

    Ashton, Driggs, Island Park, Boise, IDGuide trips
    29mi

    Madison River Outfitters

    West Yellowstone, MTGuide trips

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    Idaho season by season

    What changes on the water through the year, with the flies for each season.

    Read before you go

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    Quick answers

    Common questions about Henry's Fork of the Snake River.

    What flies work best on Henry's Fork of the Snake River?

    Our top scored fly patterns for Henry's Fork of the Snake River right now are Zebra Midge (80% confidence), Flashback Pheasant Tail Nymph (80% confidence), Blue-Winged Olive (BWO) Comparadun (80% confidence). These picks are scored from recent fishing reports, hatch data, and seasonal patterns.

    What fish species are in Henry's Fork of the Snake River?

    Henry's Fork of the Snake River holds Rainbow Trout, Mountain Whitefish. See the species links on this page for fly recommendations and seasonal behavior for each.

    What are current flow conditions on Henry's Fork of the Snake River?

    Live USGS streamflow readings for Henry's Fork of the Snake River are charted in the sidebar of this page and updated automatically from the nearest gauge.

    Is Henry's Fork of the Snake River fishing well right now?

    We publish a fresh bite report for Henry's Fork of the Snake River each week based on recent on-the-water intel. The current report — with conditions, hatches, and what's producing — is on this page.