Fishing Report - September 19, 2025

Upper Henrys Fork: 

The upper river is coming out of Island Park Reservoir at 345 CFS, with turbidity and algae still posing issues. It seems to be a day-to-day situation with people still finding nice fish in this area. Box Canyon provides good wading opportunities, with nymphing and dead drifting streamers, a great way to find fish. Most of the algae is on top of the water, so you want something that can get through that, though you may be able to find and target some rising fish. We are still hoping that the Ranch picks up in the coming days. We have been hearing word of some mahoganies showing up. We need cooler weather and perhaps rain to kick those fall-time hatches off. You can still head hunt on the ranch with rising fish spread out, but it will be some work. Still better than actual work! 

Lower Henrys Fork:

The lower Henrys is flowing at 1010 CFS near Ashton, and these fish are definitely in the fall frame of mind. Terrestrial patterns are still doing well, especially when paired with a dropper. Rubber Legs, Two Bit Hookers, Waltz Worms, and Pheasant Tails are a good place to start. Streamers are also catching some nice fish on this stretch of the river. 

South Fork of the Snake: 

The flow near Irwin is at 8030 CFS, with some fluctuations still occurring. Streamer fishing has likely been the best method of going about things on the South Fork, with deeper nymph rigs and hoppers/beetles also being productive. Mutant stones are continuing to slow, but the early riser may still be able to find some fish looking up before daylight. 

Madison River: 

Some localized caddis hatches are occurring, but terrestrials will still be the name of the game on the Madison. Our favorite flies for this area will be hoppers and beetles, with a smaller dry fly trailing (ants, parachute Adams, or even a good old Griffith’s gnat).

Teton River:

The Teton is running on the low end, 361cfs near St Anthony, but cooler weather is helping out on the water temperature side of things. Fishing continues to be productive around Driggs with both wade fishing and float opportunities. We are still waiting for the Mahogany duns and Grey Drakes to arrive. Fishing should pick up on the Teton once we start seeing more bugs, but terrestrials remain the go-to fly. 

Yellowstone National Park:

Yellowstone has been fishing well, all hoot owl restrictions have been lifted, and the fish seem to appreciate the cooler water temperatures. We have been starting to see runners in Madison. Remember, while targeting these fish, the most effective flies will be nymphs and streamers. The recommended flies are rubber legs, olive bullet quills, zebra midges, and leeches. You can also try your favorite streamer patterns; any baitfish imitation should yield some success. 

The Firehole has also been productive with caddis hatches here and there, as well as good nymphing and soft hackle opportunities. Recommended flies: White Miller Caddis, Baetis, Waltz Worm nymphs, and Pheasant Tails. 

The Gallatin within YNP is relatively low, but it is still fishing well despite that. Be stealthy with your presentation and consider sizing down in tippet—recommended flies: Terrestrials, Ants, Beetles, Hoppers. Consider dropping a small nymph off your dry; a CDC Pheasant Tail or olive bullet quills seem to get the job done on the Gallatin. 

If you want to find cutthroat trout predominantly, consider checking out the NE corner of the park. The Lamar, Slough Creek, and Soda Butte remain in good shape, with great opportunities for late-season terrestrial fishing. You may also come across some lovely drake hatches in this region—recommended flies: Hoppers, Ants, Beetles, Drakes. With the cooler nighttime temperatures we have been seeing, don’t be afraid to throw a dropper on in the morning on these rivers.   

Lakes:

Henry's Lake- The fish have started moving out of the deep water and cruising on the shoreline. Stripping small leeches and woolly buggers is a good way to target these cruising fish. Cocktail nymphs, chironomids, and flashback pheasant tails also do well under a dry or indicator. 

Hebgen- Hebgen has started to slow down, the gulpers have appeared to have turned off for the most part, and we have seen evidence of the fish staging up in preparation for the fall spawn. You can find these fish stacked, ready to move up the Madison. We recommend focusing on the rivers (the Madison and Grayling Creek) this time of year, though you can still find fish within the lake.