Lowland · Mixed · East / Meath, IE

Mongagh & Yellow Rivers

Mongagh & Yellow Rivers terrain map

Two small Boyne tributaries near Castlejordan — the Mongagh coming down from near Tyrrellspass, the Yellow from north of Daingean.

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
Proxy gauge
Level
Rising
Proxy
via Boyne
Water temp8.3°C
ClarityUnfishable
Weather2°C
WindN 7 km/h
Pressure1019 hPa
Rain · recent1.5 mm
Rain · ahead0.0 mm

No gauge on this water — conditions are inferred from Boyne. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Cool — slow
8°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 10am

12pm(now) — Black Midge

Stage: On emergersApproach: Emerger or dryActivity: 22%

Peak activity at 10am — Black Midge

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
River Deel (Meath)
15 km
0
Brown trout
Riverstown River
15 km
0
Brown trout
Enfield Blackwater
17 km
0
Brown trout
Stoneyford River
19 km
0
Brown trout
Lough Ennell
23 km
Brown trout · Pike
About this water

Both hold good stocks of small wild brown trout, with better fish to two pounds in the lower reaches below Clongall Bridge. Edenderry & Castlejordan Angling Association controls the fishing and runs it catch-and-release, with sanctuary areas in operation — so it pays to check which stretches are open before you set off.

Hatches & food

Two small mixed-geology Boyne tributaries with typical small-stream fly life — spring olives, summer Blue-Winged Olive and sedge, and a heavy reliance on black gnat and other terrestrials on the lower, slower reaches.

  • Mixed
The full read · show the working · for Brown Trout · confidence 75%
How the 0 is built — score × weight = contribution
Temperature80 × 28%22.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time50 × 13%6.5
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Conditions total= 77
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Boyneproxy
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

Mongagh & Yellow Rivers is a lowland river in East / Meath, Ireland. It sits at about 85 m above sea level. 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; short-line nymphing in pockets. Access is recorded as a water managed by an angling association or club. Nearby waters in our listings include River Deel (Meath) at 15 km, Riverstown River at 15 km and Enfield Blackwater at 17 km.