Freestone · Mixed · Montana

Dearborn River

A rocky, fast-flowing stretch of the Dearborn River winding between pine-covered canyon walls in Montana.

The Dearborn is a flashy little freestone off the Rocky Mountain Front that empties into the Missouri near Craig.

Poor · Rainbow Trout
Parachute Adams · 12-18
Poorlive now
Not the day for it
River dropping into shape after a lift. Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
90% confidence
What moved it
  • Level1.18 mDropping after lift
  • Water temp22.8°C
  • ClaritySlightly colouredClearing
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.18 m
Dropping after lift
Water temp22.8°C
ClaritySlightly coloured
Weather24°C
WindS 16 km/h
Pressure1011 hPa
Rain · recent19.0 mm
Rain · ahead0.0 mm

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

Water temperature for Rainbow Trout
Warm — slow
22.8°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 22.8°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 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
  • Short flow window — fish it early, leave it alone once it draws down
  • Yellowstone/westslope cutthroat are native here — handle and release them gently.
What's coming
Plan ahead
5-day outlook
Water here at 22.8°C. Nothing cooler within range.
Gallery · 2
  1. A rocky, fast-flowing stretch of the Dearborn River winding between pine-covered canyon walls in Montana.
    The Dearborn River
  2. Terrain map of the venue
    Terrain map
About this water

The Dearborn is a flashy little freestone off the Rocky Mountain Front that empties into the Missouri near Craig. It comes up fast and drops fast, which gives it a short, sweet window in early summer when the canyon stretch can be floated and the cutthroat and rainbows come up willingly for a dry. Miss the window and it's a bony trickle by August. People floating the famous Missouri tailwater nearby often forget it's even there, which is exactly its charm.

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

EPA ATTAINS assessment unit 'Dearborn River' (MT41Q003_010), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature. 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) · MT41Q003_010

The full read · show the working · for Rainbow Trout · confidence 90%
How the 8 is built — score × weight = contribution
Temperature4 × 28%1.1
Flow80 × 22%17.6
Clarity90 × 18%16.2
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity53 × 12%6.4
Limiting factor: Water temperature (22.8°C) is outside Rainbow Trout's preferred range (10–18°C)= 52
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
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