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Generated meadow-river scene representing Henry's Fork near Ashton in Idaho, not an exact location photo
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Henry's Fork Fishing Report — Idaho

Generated artwork: BlueStreamFly · Regional illustration; not the exact location.

Should I go fishing?

Check the water temperature first.

Water temperature is unconfirmed. Use a stream thermometer; stop trout fishing at 70°F or warmer, or sooner if fish show stress.

Rating updatedRiver local time:

Why this recommendation?

USGS shows 1,680 cfs. The flow has been stable over about 6 hours. USGS marks this reading provisional and may revise it. USGS records for this date (1923-2025, 103 readings) show a typical middle range of 1,300 cfs to 1,780 cfs. Flow is within the typical range for this date, so weather, temperature, and access become the next checks.

Available live dataHighHow much of the live flow, weather, and alert data came back.
Confidence in this recommendationMediumWater temperature not verified; do not use this score to clear warm-water risk.
Usually checks again about every 45 minutes

If you go

Check first
Use RiverReports first for the public chart, then confirm the Ashton-area trend with USGS 13046000.
Try
Decide whether you are fishing the Ashton water, Riverside reach, or ranch section before rigging up.
Leave when
Skip or switch sections when runoff, weed, storms, or crowding make the exact style of fishing you want unrealistic.

Flow and weather

Showing server-checked river conditions while current readings refresh.
Flow
1,680 cfs
From the latest stored river check. Open the official source for the newest reading.
Air forecast
64°F
Next 24h high
79.0°F

NWS air forecast near

Rain chance
1%

This is an air forecast, not a river-temperature reading. Check the water with a stream thermometer before fishing in hot weather.

Latest stored weather check

Mostly Cloudy

Wind
12 mph
Weather checked
More forecast and source details

Mostly Cloudy

National Weather Service

Henry's Fork near Ashton forecast point

The National Weather Service forecast is temporarily unavailable.

Live data

Where these readings come from

RiverReports gauge: Henrys Fork near Ashton

Official USGS station Opens in a new tab.RiverReports gauge Opens in a new tab.Official NWS forecast Opens in a new tab.

Flies for this time of year

Seasonal starting points, not a live hatch report. Match what you see on the water.

See flies for every season
SeasonWhat to look forFlies to try

Each fly name opens its matching Fly Box guide.

More fishing tips

Methods, fish species and trip notes

How to fish Henry's Fork today.

The Ashton area is strongest when flows are stable, weed load is manageable, and you know whether you want nymph water, ranch-style dry-fly water, or a float-access day. It loses value quickly if you ignore reach boundaries or show up without a flow-based section plan.

Low clear flow

Best for technical dries and lighter nymph rigs, but it also amplifies crowding and sloppy wading.

Stable medium flow

The most flexible condition for choosing between ranch-style dry fly, nymphing, or short float drifts.

High runoff push

Stay out of side channels and soft banks that make crossings or boat exits feel uncertain.

Heavy weed or moss

Downsize expectations, fish cleaner lanes, and switch reaches if the drift keeps fouling.

Wading, bank fishing or floating?
Best access methodFloating

These scores compare the risks of wading, bank fishing, and floating.

WadingNot recommended

This report does not recommend wading on this reach.

Bank fishingNot recommended

This report does not recommend bank fishing on this reach.

Floating · Best fit92/100

A float is in play where this report supports boat access and wind, releases, and shuttle logistics are manageable.

Full river report

Is Henry's Fork worth the trip today? Check flow, weather, hatches, access, and rules for Idaho before you go.

Henry's Fork is not one uniform fishery. Use the Ashton-area gauge first, then choose a reach that fits current rules, your wade-or-float plan, and the level of pressure you want to handle.

Fishing words used on this page
U.S. Geological Survey (USGS) gauge
A USGS gauge is an official river station that measures flow or water height.
Cubic feet per second (cfs)
Cubic feet per second, or cfs, shows how much water passes the gauge each second.
Technical fishing
Technical fishing means the fish are hard to fool, so careful casts and natural drifts matter.
Nymph
A nymph is a young water insect. Anglers also use the word for a fly that copies it.
Riffle
A riffle is shallow, fast water broken by rocks.
Blue-winged olive (BWO)
Blue-winged olives, or BWOs, are small mayflies that often hatch in cool or cloudy weather.
Caddis
Caddis are small water insects. The adults look a little like tiny moths.
Dry-dropper
A dry-dropper rig has a floating fly with an underwater fly tied below it.
Emerger
An emerger copies an insect as it rises from below the water toward the surface.
Midge
Midges are tiny flies and a common trout food, especially in cold water.
Why this call

Why this score

FlowHelps

USGS shows 1,680 cfs. The flow has been stable over about 6 hours. USGS marks this reading provisional and may revise it. USGS records for this date (1923-2025, 103 readings) show a typical middle range of 1,300 cfs to 1,780 cfs. Flow is within the typical range for this date, so weather, temperature, and access become the next checks.

SeasonHelps

Early fall: Often the cleanest balance of cooler nights, steady trout feeding, and less crowding.

WeatherHelps

The current NWS air forecast is about 64F, and the next 24-hour high reaches about 79F. Mostly Cloudy.

Public alertsHelps

No active NWS alert was returned for this forecast point.

Fishing usefulnessHelps

Skip or switch sections when runoff, weed, storms, or crowding make the exact style of fishing you want unrealistic.

Trip notes

Check these before you choose a reach.

Best flows

Stable moderate flows that keep weed, side channels, and bank softness manageable while still letting trout hold in predictable lanes.

When to leave

Skip or switch sections when runoff, weed, storms, or crowding make the exact style of fishing you want unrealistic.

Local plan

Check the Ashton graph first, decide whether you want technical dry-fly water or more forgiving riffles, then commit to one section instead of trying to sample the whole river.

Backup water

If Henry's Fork is too crowded or technical for the day you want, look at the South Fork Snake for a different scale or Big Wood for a simpler freestone rhythm after checking current conditions.

Henry's Fork access and rules.

Use these places as starting points. Open the access link below and check posted signs before you park or enter.

Before you go

IDFG lists reach-by-reach Henry's Fork rules, including catch-and-release periods, barbless-hook water, no-bait sections, and the seasonal closure through June 14 on the Harriman Ranch section. Check the current 2025-2027 rules before choosing a reach.

Where to access the river

Ashton-area public access and dam area

Best starting point for gauged water and lower-upper area decisions.

Riverside Campground reach

Useful official Forest Service anchor for the upper Ashton area and nearby walk-in water.

Red Road Bridge and downstream BLM access

Official lower-river float and bank access that matters when your plan drifts below the classic Ashton water.

  • IDFG makes it clear the Henry's Fork has section-specific rules, so do not assume one reach's rule set applies to the whole river.
  • The BLM Red Road and related downstream sites are most useful when you are planning a St. Anthony-to-Menan style float, not a classic Harriman walk-and-wade day.
  • Campground, boat-ramp, and state-park popularity make early parking and shuttle discipline part of the plan in summer.

If this water does not fit the day, check another report before you start the drive.

IdahoBig Wood River fishing reportA valley freestone alternative with simpler access and less legendary-river pressure.
See all Idaho fly fishing reports

Sources and report details

Official agencies and primary river operators come first. Secondary tools are labeled so you know what carries the most weight.

Rules and closures

Check what is allowed, where the rule applies, and whether the river is open.

Flow and weather

Check the latest river reading and forecast before you leave.

Access and land

Check public entry points, land rules, and seasonal access changes.

See all 6 checked sources

Rules and closures

Check what is allowed, where the rule applies, and whether the river is open.

Flow and weather

Check the latest river reading and forecast before you leave.

Access and land

Check public entry points, land rules, and seasonal access changes.

Source check is old. Last checked . Open the official links now and check for changes.

See something wrong? Report a source problem. Please do not send private spots or private access notes.

How this report was checked

How this report was checked

Trip guidance checked

What was checked: This report uses official regulation, flow, weather, access, and public-land sources first, then adds practical planning guidance for fly anglers.

Live measurements and forecasts keep their provider timestamps. Rules, access, and trip guidance use the source-review date shown here. BlueStreamFly planning advice is editorial interpretation, not an agency notice.

First-hand experience: BlueStreamFly does not claim a first-hand visit or local field test for this report unless a real contributor is explicitly named and linked.

Quick questions

Which Henry's Fork reach does this page cover?

This page is centered on the Ashton gauge area, including Ashton Dam access, Riverside water, and the nearby classic upper river decision points.

Can I treat all of Henry's Fork the same way?

No. IDFG publishes section-specific rules, and the fishing styles change a lot from the lower float river to the technical upper water.

What gauge should I start with?

Start with RiverReports and USGS 13046000 near Ashton for this page's area, then match that reading to your specific section plan.