Freestone · Mixed · Montana

Stillwater River

Stillwater River — Stillwater River (near the Stillwater Mine, Beartooth Mountains, Montana, USA) 1

The Stillwater is misnamed and proud of it — a fast, tumbling freestone off the Beartooth front that never sits still for a second.

Marginal · Rainbow Trout
Parachute Adams · 12-18
Marginallive now
Slow going — pick your moments
River dropping into shape after a lift. A short window. Take your time.
90% confidence
What moved it
  • Level1.06 mDropping after lift
  • Water temp18.0°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.06 m
Dropping after lift
Water temp18.0°C
ClarityClear
Weather21°C
WindSW 8 km/h
Pressure1014 hPa
Rain · recent5.6 mm
Rain · ahead0.2 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Rainbow Trout
Ideal
18.0°Cideal 10–18°C
0°14°28°
How to fish it · for Rainbow Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 18°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
2
1
1
2
2
2
2
2
2
2
Western Green DrakeHatch
2
2
Flav (Small Western Green Drake)Hatch
2
3
2
Mahogany DunHatch
2
2
American March BrownHatch
2
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Montana licence
  • Yellowstone/westslope cutthroat are native here — handle and release them gently.
What's coming
Plan ahead
5-day outlook
Water here at 18.0°C. Nothing cooler within range.
Gallery · 2
  1. Stillwater River — Stillwater River (near the Stillwater Mine, Beartooth Mountains, Montana, USA) 1
    Stillwater River (near the Stillwater Mine, Beartooth Mountains, Montana, USA) 1
  2. Terrain map of the venue
    Terrain map
About this water

The Stillwater is misnamed and proud of it — a fast, tumbling freestone off the Beartooth front that never sits still for a second. Rainbows, browns, and cutthroat live in the pockets and pools. Once the snowmelt runs off in summer it settles into fine pocket-water dry-fly fishing, the kind where you read the water boulder by boulder and wade like you mean it.

  • Mixed
Water quality · US Clean Water Act
  • Aquatic life: Impaired
What this classification means

EPA ATTAINS assessment unit 'Stillwater River' (MT43C001_020), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Nutrients, Metals Other Than Mercury, Mercury, Toxic Inorganics. This is a Clean Water Act assessment-unit classification (the US analogue of WFD), not a live reading.

Status is for the Clean Water Act assessment unit covering this reach.

EPA ATTAINS (Clean Water Act) · MT43C001_020

The full read · show the working · for Rainbow Trout · confidence 90%
How the 40 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time55 × 13%7.2
Pressure75 × 7%5.3
Insect activity62 × 12%7.4
Conditions total= 81
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • TroutThird Saturday of May → Last day of February
Related guides
Euro Nymphingsubsurface methods
Booking & contacts