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Home › Waters › Idaho › Henrys Fork
Tailwater · Eastern Idaho · Idaho

Henrys Fork Fishing Guides

The most famous dry fly river in America, from the Box Canyon and Harriman Ranch flats through Mesa Falls to the canyon water above Ashton.

A river winding through a deep canyon at sunset in the mountain West

Map of the Henrys Fork

21 numbered points: 9 access points, 5 campsites, 1 bridge, 1 park or conservation area, 3 hazards, 1 spring, 1 USGS gauge. Tap a marker for details. Reviewed Sep 8, 2026.

Printable version →
  • Access / boat ramp (9)
  • Campsite (5)
  • Bridge crossing (1)
  • Park / conservation area (1)
  • Dam / hazard (3)
  • Spring (1)
  • USGS gauge (1)
Map data © OpenStreetMap contributors. Points are curated from OpenStreetMap and state agency sources; confirm access and hours before you go.

Print it. Bag it. Bring it.Phones die, screens crack, and most of this water has no signal. Print this map, fold it into a zip-top bag or dry bag with your license, and you have a backup your electronics can’t give you. Every marker is numbered so you can say exactly where you are.

Open the printable map
All 21 points on this map
#PointTypeLat, LonNotes
1Big Springs
Caribou-Targhee National Forest		Spring44.50057, -111.25496Source of the Henrys Fork - a large constant-temperature spring that starts the river at full size.
2Big Springs Campground
Caribou-Targhee NF		Campsite44.49753, -111.25448
3Upper Coffeepot Campground
Caribou-Targhee NF		Campsite44.49058, -111.36676
4McCrea Bridge Campground
Caribou-Targhee NF		Campsite44.46224, -111.40054
5McCrea Bridge boat ramp
OSM: unnamed slipway on McCrea Road		Access / boat ramp44.46141, -111.40159At the head of Island Park Reservoir; the usual take-out for the Big Springs and Coffee Pot water.
6Island Park Dam
Bureau of Reclamation		Dam / hazard44.41872, -111.39624
7USGS 13042500 Henrys Fork near Island Park
Real-time flow and stage		USGS gauge44.41667, -111.39472Check the reading before you commit to a float; releases and runoff move this river fast.
8Boat ramp below Island Park Dam
OSM: unnamed slipway on Forest Road 563		Access / boat ramp44.41613, -111.39501Head of the Box Canyon reach.
9Box Canyon Campground
Caribou-Targhee NF		Campsite44.41019, -111.39605
10Boat ramp at Last Chance
OSM: unnamed slipway on Old Highway		Access / boat ramp44.37115, -111.40275Foot of Box Canyon and head of the Last Chance flat water.
11Harriman State Park
Idaho Parks & Recreation		Park / conservation area44.33603, -111.46135The Railroad Ranch water; park access is on foot from the park lots.
12Osborne Bridge
Highway crossing at the foot of the Ranch		Bridge crossing44.32472, -111.44859
13Riverside Campground boat ramp
OSM: unnamed slipway on Riverside Campground Road		Access / boat ramp44.26678, -111.45615
14Mesa Falls
Waterfall on the Henrys Fork		Dam / hazard44.18765, -111.32976OSM maps a single 'Mesa Falls' node here at the upper falls; the lower falls are a short way downstream. No boat passage through this canyon.
15Grandview Campground
Caribou-Targhee NF		Campsite44.17487, -111.31355
16Boat ramp on North River Road
Unnamed in OSM		Access / boat ramp44.10942, -111.33801Above Ashton Reservoir.
17Ashton Dam
Hydro dam on the Henrys Fork		Dam / hazard44.07850, -111.49687
18Boat ramp on East 1300 North
Unnamed in OSM		Access / boat ramp44.06995, -111.51054Below Ashton Dam.
19Boat ramp on 2830 North
Unnamed in OSM		Access / boat ramp44.01816, -111.58245Chester to Saint Anthony reach.
20Boat ramp on South River Road
Unnamed in OSM		Access / boat ramp43.98290, -111.62394Above Saint Anthony.
21Boat ramp on North 1900 East
Unnamed in OSM		Access / boat ramp43.92736, -111.77847Below Saint Anthony, on the run down to the Snake.

Guides on the Henrys Fork

Claimed profiles take booking requests. Unclaimed profiles are built from public records so the river is never empty; the guide can claim or remove one any time.

About the Henrys Fork

The Henry’s Fork is where American dry fly fishing set its standard for difficulty. The river rises at Big Springs, flows through Island Park Reservoir, and then delivers two of the best-known reaches in the sport: the Box Canyon, fast pocket water full of large rainbows, and the Harriman Ranch, three miles of flat, weedy, glassy spring creek where the fish are big, the currents are complicated, and refusals are the normal outcome. Below that the river drops over Upper and Lower Mesa Falls into a canyon and then out into the Ashton tailwater.

The Ranch is the reason people plan trips a year ahead. Green drakes in June, pale morning duns and callibaetis through the summer, and tricos and mahoganies in the fall come off water so slow you can see every rise form. Long leaders, exact drifts and patience are the whole game, and it is fished on foot with no wading in some sections during the nesting season. The Box Canyon, by contrast, is a nymph and streamer fishery with the biggest fish in the system.

The Island Park gauge reads the release into the Box Canyon. Roughly 600 to 1,200 cfs is normal working water there; irrigation season pushes it higher, and drawdown in the fall changes conditions quickly. The Ranch fishes on whatever comes down from the Box, and its slow, weedy character means the flow number matters less than the wind and the hatch.

Island Park, Last Chance and Ashton are the base, with West Yellowstone forty minutes away over Targhee Pass. Come with more patience than tackle, and consider hiring a guide the first time on the Ranch.

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We choose which photos to publish and may decline any submission without giving a reason. We may crop, resize, sharpen or colour-correct a photo for display, and we may remove a photo at any time. We will not alter a photo in a way that misrepresents the fish, the water or you.

6. Your details

We keep your name, email address, the credit name, the water and date you gave us, and the network address the submission came from, with the submission record, as our evidence of this license. We hold that record for as long as the photo is published and for the retention period described in our privacy policy. Location data that your camera or phone embedded in the file is removed before the photo is published.

7. Versions

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Posting to Henrys Fork.

JPG, PNG or WebP, up to 12 MB. We resize it and strip the location data out of the file.

The name shown under the photo. Leave blank to stay anonymous.

Reader photo license v1.0 — the short version:

  • You grant Guided Floats, LLC a non-exclusive, royalty-free license to publish, resize and crop your photo on guidedfloats.com and in GuidedFloats’ own social posts and apps. You keep the copyright and can use the photo anywhere else.
  • You confirm that you took the photo yourself, that publishing it does not infringe anyone else’s rights, and that anyone recognisable in it (or a parent or guardian, if they are under 18) is happy for it to appear here.
  • Credit is printed beside the photo wherever it appears on the site, using the credit name you give us. Leave it blank and we use your name; write “Anonymous” for no name. Your email address is never published.
  • Withdrawing is one email to hello@guidedfloats.com naming the photo. It comes off the site within 7 days.
Read the full license

Version 1.0, dated 6 September 2026. Applies to every photograph submitted to GuidedFloats through the contact form, a species page, or the community board.

1. What you give us

By ticking the box on the form you grant Guided Floats, LLC (“GuidedFloats”, “we”) a non-exclusive, worldwide, royalty-free license to store, copy, resize, crop and display your photograph on guidedfloats.com, in GuidedFloats’ own social media accounts and mobile apps, and in material that promotes the site itself, in connection with the fish, water or community feature you sent it in for. The license lasts until you withdraw it (section 4).

You keep the copyright. The license is not exclusive, so you can use the photo anywhere else and license it to anyone else. We will not sell your photo, license it on to anyone else on its own, or use it in paid advertising for a third party.

2. What you confirm

You confirm that you took the photograph yourself (or otherwise own the rights to it), that you have the right to grant this license, and that publishing the photo does not infringe anyone else’s copyright, privacy or other rights.

If any person is recognisable in the photo, you confirm that they have agreed to its being published here, and that a parent or guardian has agreed on behalf of anyone under 18. Please do not send photographs of other people’s catches, screenshots, or pictures copied from other websites or social media.

3. Credit

We print the credit name you give us beside the photo wherever it appears on the site, and record it as the photo’s creator in the page’s structured data. If you leave the credit blank we use the name you gave us on the form. Write “Anonymous” if you prefer no name at all. Your email address, phone number and the exact spot the photo was taken are never published.

4. Withdrawing the license

You can withdraw the license at any time by emailing hello@guidedfloats.com, or by using the contact form, and telling us which photo you mean. We will remove the photo from guidedfloats.com within 7 days of receiving your message and stop using it in anything new. Copies that are already outside our control — search-engine caches, social posts that have already gone out, printed material already produced — may take longer to disappear or may not be recallable, and we are not responsible for those.

5. What we may do

We choose which photos to publish and may decline any submission without giving a reason. We may crop, resize, sharpen or colour-correct a photo for display, and we may remove a photo at any time. We will not alter a photo in a way that misrepresents the fish, the water or you.

6. Your details

We keep your name, email address, the credit name, the water and date you gave us, and the network address the submission came from, with the submission record, as our evidence of this license. We hold that record for as long as the photo is published and for the retention period described in our privacy policy. Location data that your camera or phone embedded in the file is removed before the photo is published.

7. Versions

The version of this license you accepted is stored with your submission and printed with the photo. A later version does not apply to a photo you have already sent unless you agree to it.

Flow alert

Tell me when the Henrys Fork cfs

Now: 91.9 cfs, read 5:45 pm CDT, Sun Oct 18, 2026 (USGS 13042500, HENRYS FORK NR ISLAND PARK ID).

We never use this address for anything else and never share it. See the privacy policy.

Access

Big Springs: the headwaters, a no-fishing spring with enormous visible trout.
Mack's Inn and Coffee Pot Rapids: upper river access above the reservoir.
Box Canyon: below Island Park Dam near the gauge, boat launch and walk-in access.
Last Chance and the Harriman Ranch: the famous flat water, walk-in from the state park.
Harriman State Park: parking, trails and seasonal access rules.
Riverside and Hatchery Ford: canyon access above Mesa Falls.
Warm River and Ashton: the lower river and the tailwater reach.

Seasons

Late May through November on most reaches; the Ranch opens on a set date each June.
June: salmonflies in the canyon and green drakes on the Ranch, the peak of the year.
July and August: pale morning duns, callibaetis, terrestrials and technical flat-water fishing.
September and October: mahoganies and tricos, then streamers as the crowds leave; the Box fishes all winter where open.

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Questions

What is the current flow on the Henrys Fork?

As of Oct 18, 5:45 pm, the USGS gauge HENRYS FORK NR ISLAND PARK ID reads 92 cfs, the 9th percentile for this date. Conditions update every 15 minutes.

What species can you catch on the Henrys Fork?

Anglers target Brook Trout, Brown Trout, Cutthroat Trout, Mountain Whitefish, Rainbow Trout on the Henrys Fork in Idaho.

Are there fishing guides on the Henrys Fork?

GuidedFloats lists 4 guides and outfitters on the Henrys Fork. Claimed profiles accept booking requests; unclaimed profiles are built from public records and link to the business.

Where can you access the Henrys Fork?

Big Springs: the headwaters, a no-fishing spring with enormous visible trout. Mack's Inn and Coffee Pot Rapids: upper river access above the reservoir. Box Canyon: below Island Park Dam near the gauge, boat launch and walk-in access. Last Chance and the Harriman Ranch: the famous flat water, walk-in from the state park. Harriman State Park: parking, trails and seasonal access rules. Riverside and Hatchery Ford: canyon access above Mesa Falls. Warm River and Ashton: the lower river and the tailwater reach.

When is the best time to fish the Henrys Fork?

Late May through November on most reaches; the Ranch opens on a set date each June. June: salmonflies in the canyon and green drakes on the Ranch, the peak of the year. July and August: pale morning duns, callibaetis, terrestrials and technical flat-water fishing. September and October: mahoganies and tricos, then streamers as the crowds leave; the Box fishes all winter where open.

Where are the fishing regulations for the Henrys Fork?

Regulations change by season and section. Read the current rules on the Idaho agency site: https://idfg.idaho.gov/rules/fish