Western Montana Fly Fishing Report
Current Restrictions and Closure Summary
Montana FWP currently lists no hoot-owl fishing restrictions on the Bitterroot, Blackfoot, Clark Fork, Rock Creek, or West Fork Bitterroot.
- Blackfoot River: Closed to floating from Weigh Station Fishing Access Site downstream to the point where the river crosses beneath Interstate 90 because of railway bridge construction.
- Rock Creek: Regular seasonal regulations prohibit fishing from boats or vessels from July 1 through November 30. Plan on wade fishing only.
- Check before heading out: Emergency restrictions can change, so verify the current Montana FWP page before launching or fishing.
Regional River Conditions Overview
The heavy early-September rain bump has been receding, but the region remains in much better shape than it was during late August. The Bitterroot, Blackfoot, Clark Fork, and Rock Creek are still carrying useful additional water, while the West Fork continues to benefit from managed flows.
Cool nights are shifting the fishing schedule later. Instead of expecting the best dry-fly activity at first light, plan on getting serious around 9:00 a.m. and watching for Tricos into late morning. Terrestrials remain productive once the day warms, and cooler cloudy periods should bring Mahoganies, BWOs, Hecubas, and streamers into play.
Sunday through Tuesday look particularly good for anglers who prefer mayflies and streamers. Wednesday through Saturday turn somewhat warmer and brighter, which should favor Tricos in the morning followed by terrestrial and dry-dropper fishing.
Bitterroot River
Conditions
The Bitterroot has settled nicely after the Labor Day rain bump. The latest verified readings reviewed for this report show roughly 529 CFS near Darby, about 711 CFS at Bell Crossing, and around 1,172 CFS near Missoula. The river is dropping from last week's high point but still has considerably more water and better holding structure than it did during late August.
The Bitterroot is entering one of the more interesting hatch transitions of the year. Tricos remain the morning anchor, terrestrials remain important around midday, and Hecubas, Mahoganies, BWOs, and October Caddis are beginning to appear more consistently.
Where to Fish
- Soft tailouts and slicks during Trico spinner activity
- Riffle edges transitioning into deeper green water
- Foam lines and inside seams
- Grassy and undercut banks for terrestrials
- Deeper buckets and shelves during cloudy streamer windows
- Long slower seams when fall mayflies begin emerging
How to Fish It
- Do not rush the Trico hatch. Cooler mornings may push spinner activity toward mid-morning
- Fish Trico spinners and clusters to visibly feeding trout
- Prospect hoppers, ants, and beetles along banks after the Trico window
- Carry Hecubas, Mahogany Duns, and BWOs for cloudy periods
- Fish October Caddis pupa below a terrestrial or attractor dry
- Use Frenchies, Pheasant Tails, Perdigons, and small caddis pupa through riffle edges
- Streamer fish banks, shelves, and deeper seams during clouds and showers
Top Patterns
- Trico spinner or cluster, size 18–22
- Hecuba / Fall Drake, size 10–12
- Mahogany Dun, size 14–16
- BWO dry or emerger, size 18–22
- October Caddis adult or pupa, size 8–12
- Hopper, ant, or beetle, size 8–18
- Olive, black, or tan streamer, size 4–8
Blackfoot River
Conditions
The latest verified Blackfoot reading near Bonner was around 893 CFS following the early-September rain. The river is carrying significantly more water than it did through much of August and is fishing more like an early-fall river.
Terrestrials remain useful, but the fall transition is underway. Cooler weather improves the streamer game, while October Caddis activity should continue building as September progresses.
Where to Fish
- Boulder edges and plunge pools
- Fast riffle transitions
- Deep buckets and shaded banks
- Foam lines below structure
- Grassy edges for remaining terrestrials
- Inside seams and slower shoulders during mayfly activity
How to Fish It
- Prospect with hoppers and foam attractors around banks and boulder water
- Drop a Frenchie, Perdigon, caddis pupa, or Pheasant Tail below the dry
- Carry October Caddis adults and pupa
- Look for Tricos in softer late-morning water
- Streamer fish banks and deeper buckets on cloudy days
- Use olive, tan, black, or white depending on clarity and light
- Plan all floats around the Weigh Station closure
Top Patterns
- October Caddis adult or pupa, size 8–12
- Hopper or foam attractor, size 8–12
- Ant or beetle, size 12–18
- Trico spinner, size 18–22
- Perdigon or Frenchie, size 14–18
- Caddis pupa, size 12–18
- Olive, tan, black, or white streamer
Clark Fork River
Conditions
The Clark Fork continues to benefit from the early-September rain. Latest verified readings are around 1,696 CFS above Missoula and roughly 2,726 CFS below Missoula. That is substantially healthier than the low flows of August.
The Clark Fork may offer some of the most interesting dry-fly fishing this week. Tricos are still strong but are increasingly occurring later in the morning as overnight temperatures cool. Mahoganies and small BWOs are becoming more common, while terrestrials remain useful between hatch windows.
Where to Fish
- Long slicks and tailouts during Tricos
- Riffle edges and foam lines
- Inside seams and current tongues
- Grassy islands and undercut banks
- Side channels with depth and current
- Deep structure during cloudy streamer windows
How to Fish It
- Watch before casting and locate feeding pods during the Trico spinner fall
- Use long leaders and fine tippet when head hunting
- Switch to hoppers, ants, and beetles once the spinner activity fades
- Carry Mahogany Duns and BWOs for cloud cover
- Nymph Frenchies, Pheasant Tails, Perdigons, and caddis pupa through riffle edges
- Streamer fish banks and deeper seams during darker weather
Top Patterns
- Trico spinner or cluster, size 18–22
- Mahogany Dun, size 14–16
- BWO dry or emerger, size 18–22
- Hecuba, size 10–12
- Hopper, ant, or beetle, size 8–18
- Caddis / October Caddis, size 8–18
- Olive, tan, or black streamer
Rock Creek
Conditions
The latest verified Rock Creek reading near Clinton was around 372 CFS and receding after a significant early-September rain bump. The creek has more water than it carried during late August while remaining very manageable for wade anglers.
Rock Creek is now firmly in the summer-to-fall transition. Hoppers, ants, and beetles are still productive, Tricos are appearing later in the morning, and Hecubas, Mahoganies, and BWOs should become increasingly important.
Where to Fish
- Pocket water and boulder cushions
- Riffle drops and deeper slots
- Undercut banks and shaded edges
- Soft tailouts during Trico activity
- Foam lines below faster water
- Deep buckets during streamer conditions
How to Fish It
- Fish terrestrials and small attractors through pocket water
- Look for Tricos from mid-morning toward noon
- Carry Hecuba, Mahogany, and BWO patterns
- Use Frenchies, Perdigons, Pheasant Tails, and caddis pupa as droppers
- Streamer fish deeper pockets when cloud cover increases
- Stay low and make the first cast count
- Remember that Rock Creek is wade fishing only during the current seasonal boat restriction
Top Patterns
- Hopper, ant, or beetle, size 8–18
- Trico spinner, size 18–22
- Hecuba, size 10–12
- Mahogany Dun, size 14–16
- BWO, size 18–22
- Frenchie or Perdigon, size 14–18
- Olive or black streamer, size 4–8
West Fork of the Bitterroot
Conditions
The latest verified West Fork reading near Conner was around 322 CFS, well above the historical median for the date. Managed flows continue to make the West Fork one of the more reliable smaller-water choices in the Bitterroot drainage.
The West Fork is also showing a more legitimate fall program now. Hecubas are worth carrying, along with Tricos, terrestrials, caddis, nymphs, and small streamers.
Where to Fish
- Riffle edges and pocket water
- Protected tailouts and inside seams
- Foam lines beside structure
- Deeper pockets below wood and boulders
- Soft glides during mayfly activity
- Overhanging grass for terrestrials
How to Fish It
- Look for Tricos later in the morning
- Carry Hecuba dries and larger mayfly patterns
- Fish ants, beetles, and small hoppers around banks
- Use Perdigons, Pheasant Tails, Lightning Bugs, and Frenchies below a dry
- Try small bright or olive streamers through deeper pockets
- Use longer leaders and careful first casts in softer water
Top Patterns
- Hecuba, size 10–12
- Trico spinner, size 18–22
- Hopper, ant, or beetle, size 10–18
- Caddis, size 14–18
- Perdigon or Pheasant Tail, size 14–18
- Small olive or bright streamer
Planning Note
Sunday through Tuesday: The cooler, cloudier part of the week. Do not rush to the river at dawn. Give the water a little time to warm and look for Tricos around mid-morning, followed by Hecubas, Mahoganies, BWOs, terrestrials, and streamers as conditions dictate.
Wednesday through Friday: Warmer and brighter. Tricos should remain important in the morning, followed by hopper, ant, beetle, and dry-dropper fishing. Thursday's possible afternoon thunderstorm could create a short streamer or mayfly window.
Saturday: Mostly cloudy and warm enough to keep insect activity moving. This could be another good mixed-bag day with Tricos, terrestrials, fall mayflies, and streamers all worth carrying.
The biggest tactical change from August is simple: you no longer need to fish at sunrise to get the best window. Cooler nights are moving the hatch clock later. A 9:00 or even 10:00 a.m. start can be exactly right on some sections.
River Flow Snapshot – September 13, 2026
These are the latest numerical readings that could be independently verified for each gauge when this report was prepared. Several USGS feeds were reporting data through September 10–12 rather than September 13. USGS readings are provisional.
| River | Section | Gauge | Latest Verified Flow | Status |
|---|---|---|---|---|
| Bitterroot | Upper | Near Darby (12344000) | 529 CFS | Good Early-Fall Shape |
| Bitterroot | Middle | Bell Crossing nr Victor (12350250) | 711 CFS | Receding After Rain Bump |
| Bitterroot | Lower | Near Missoula (12352500) | 1,172 CFS | Improved / Receding |
| Blackfoot | Lower | Near Bonner (12340000) | 893 CFS | Good Fall Flow / Float Closure Below Weigh Station |
| Clark Fork | Upper | Above Missoula (12340500) | 1,696 CFS | Good Early-Fall Flow |
| Clark Fork | Lower | Below Missoula (12353000) | 2,726 CFS | Healthy September Flow |
| Rock Creek | Lower | Near Clinton (12334510) | 372 CFS | Good Wade Shape / No Boat Fishing |
| West Fork Bitterroot | Lower | Near Conner (12342500) | 322 CFS | Managed / Above Median |
The regional flow picture remains considerably better than it was in late August. Rivers are receding from the Labor Day rain bump, but trout still have more depth, cover, and usable holding water than they had several weeks ago.
Fly Box of the Week
Dry Flies
- Trico spinner / cluster, size 18–22
- Hecuba / Fall Drake, size 10–12
- Mahogany Dun, size 14–16
- BWO dry / emerger, size 18–22
- October Caddis, size 8–12
- Hopper, size 8–12
- Ant / beetle, size 12–18
Nymphs
- Frenchie, size 14–18
- Perdigon, size 14–20
- Pheasant Tail, size 14–20
- BWO nymph, size 18–22
- Caddis pupa, size 12–18
- October Caddis pupa, size 8–12
- Jigged Hare's Ear, size 14–18
Streamers
- Sculpzilla
- Thin Mint
- Woolly Bugger
- Sparkle Minnow
- Mini Dungeon
- Olive sculpin
- Black or tan streamer
Hatch and Fly Chart – Mid-September Edition
| Hatch / Insect | Activity | Best Time | Recommended Fly | Size |
|---|---|---|---|---|
| Tricos | Still a major hatch, but cooler mornings are delaying spinner activity | Mid-morning to noon | Spinner or cluster | 18–22 |
| Hecubas | Increasing and becoming a legitimate fall target | Late morning through afternoon | Hecuba, Brindlechute, rusty mayfly | 10–12 |
| Mahogany Duns | Increasing across the system | Late morning through afternoon | Mahogany dry, cripple, or emerger | 14–16 |
| BWOs | Best during clouds, showers, and cooler weather | Late morning through afternoon | BWO dry, emerger, or nymph | 18–22 |
| Terrestrials | Still important; do not put the hopper box away yet | Late morning through afternoon | Hopper, ant, beetle | 8–18 |
| October Caddis | Beginning to show and becoming increasingly important | Variable, often later in the day | October Caddis adult or pupa | 8–12 |
This is now a true crossover hatch menu. Tricos and terrestrials are still productive enough that abandoning them would be a mistake, while Hecubas, Mahogany Duns, BWOs, and October Caddis are beginning to define the fall program.
Gear Picks of the Week
Fall Mayfly Box
Hecubas, Mahoganies, BWOs, and Tricos now deserve their own organized section. The days of digging through the July box looking for something approximately brown are over.
Long Leaders and Fine Tippet
Trico fishing and clear September water still reward precision. Keep 5X and 6X available and lengthen leaders when targeting feeding pods.
Streamer Box
Fall streamer season is waking up. Carry olive, black, tan, and lighter baitfish options so you can adjust to water clarity and cloud cover.
Strategy and Expectations This Week
The Bitterroot remains the best overall local option. It offers the widest mix of Tricos, terrestrials, fall mayflies, dry-droppers, and streamer opportunities.
The Clark Fork is the best choice for dedicated dry-fly anglers. Cooler mornings are delaying the Trico action, which can create excellent late-morning feeding pods. Mahoganies and BWOs are becoming increasingly important.
Rock Creek is the best wade-fishing option. The water is still carrying some benefit from the early-September rain, and fall insects are beginning to join the terrestrial program.
The Blackfoot is becoming a stronger fall option. Streamers and October Caddis deserve more attention each week, but the Weigh Station floating closure still has to be built into every float plan.
The West Fork remains the most dependable smaller-water option. Managed flows are strong for the date, and Hecuba fishing is becoming legitimate.
