Lowland · Limestone · Shannon / Offaly, IE

River Brosna

River Brosna terrain map

A limestone river rising from Lough Ennell and running through Offaly to the Shannon, with wild brown trout, a croneen (migratory trout) presence and small summer salmon runs.

Tomorrow · Closed season
Czech Nymph
Forecast · Tomorrow
Closed season
Out of season. Try elsewhere.
45% projected
Today's fly
Czech Nymph
Czech Nymph
Conditions on the water · Tomorrow
Live gauge
Level
Rising
0.83 m
Lifting fast
Water temp10.2°C
ClarityVery coloured
Weather2°C
WindN 6 km/h
Pressure1019 hPa
Rain · recent2.1 mm
Rain · ahead0.0 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Ideal
10°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown 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.
Likely species
Stoneflies
Gammarids
Hatch timeline · tomorrowPeak at 6pm

12pm(now) — Autumn Olive

Stage: On emergersApproach: Emerger or dryActivity: 23%

Peak activity at 6pm — Caperer (Caperer, Weather boost)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · November highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Mayfly (Green Drake)Hatch
2
2
Large Cinnamon SedgeHatch
2
3
3
2
Daddy Long LegsHatch
2
3
3
2
CapererHatch
2
3
3
2

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

Ranked for today
Brown Trout fly box
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Camcor River
29 km
0
Brown trout
Pallas Lake
13 km
Rainbow trout · Brown trout
Mount Dalton Lake
20 km
Brown trout
Lough Ennell
21 km
Brown trout · Pike
Lough Owel
30 km
Brown trout
About this water

Classic midland water, best before the summer weed.

Hatches & food

EPA river-invertebrate monitoring confirms mayflies, stoneflies, caddis, aquatic diptera and freshwater crustaceans are present across the Brosna's monitored segments. This is food-presence evidence only, drawn from kick samples, and doesn't establish emergence timing or the strength of any visible hatch.

  • Limestone
The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity71 × 12%8.5
Conditions total= 84
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 March → 30 September
Related guides
ConnemaraIrish fishingEuro Nymphingsubsurface methods
Casting instructors near here
Booking & contacts
Permits & access
At a glance

River Brosna is a lowland river in Shannon / Offaly, Ireland. Its recorded elevation is about 70 m above sea level and the catchment geology is limestone. The species listed for this water is brown trout. The trout season is recorded as running from 1 March to 30 September. Core methods listed: upstream dry fly; upstream nymph; spider. Level and flow data for this water is linked from 1 gauge. Nearby waters in our listings include Pallas Lake at 13 km, Mount Dalton Lake at 20 km and Lough Ennell at 21 km.