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By Gary
Carn Mairg
Photo: Iain Russell / CC BY-SA 2.0 via Geograph
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Munro · Fife & Perthshire

Carn Mairg

Càrn Mairg (1043m) is the highest of the four Munros of the Càrn Mairg group, the long ridge of summits that walls in the northern side of Glen Lyon — Scotland's longest enclosed glen. The group also includes Meall Garbh, Càrn Gorm and Meall na Aighean (Creag Mhòr), and the full traverse takes in all four with a long high-level ridge connecting them. The hills are mossy and grassy in character rather than rocky, offering one of the most enjoyable horseshoe rounds in southern Scotland.

Quick facts

Height
1043m/ 3422ft
Prominence
467 m
Distance
~17 km
Ascent
~918 m
Time
58 hrs
Difficulty
4 / 5Serious
Grid ref
NN684512
Parking
NN666483
Nearest city
Perth· 51km
Dogs
Dogs on lead required near livestockDog-friendly guide ↗

Height and prominence cross-checked against the Database of British and Irish Hills (CC BY).

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Standard route

Glen Lyon track 25% · Open hillside 45% · Summit ridge 30%

17km · 918m ascent · 4.9 hrs

Park at Invervar on the north side of Glen Lyon, west of Coshieville. Take the path north up the Invervar Burn, then climb west onto Càrn Gorm — the first Munro. Continue north and east over Meall Garbh and Meall a' Bharr, then north-east to Càrn Mairg. Drop south-east to the bealach and climb the final Munro, Meall na Aighean (Creag Mhòr), before descending the south ridge back to Invervar. Around 17km with 1300m of ascent for the full four-Munro round.

Terrain

The Invervar Burn path is firm peaty track for the first kilometre, then deteriorates onto open hillside. The four summits are linked by broad mossy turf ridges that are pleasant under foot but undulate continuously — there is more re-ascent than the map suggests. The Càrn Mairg summit is a small cairn perched on a flat top covered with quartzite boulders. The descent off Meall na Aighean to Invervar is steep wet grass.

In winter

A long winter ridge traverse. The broad mossy summits drift deeply but offer few avalanche-prone slopes. The two deep bealachs collect wind-blown snow and can be tiring underfoot. Each of the four tops develops consistent cornicing along its northern flank. The Glen Lyon road is a narrow single-track route prone to drifts. Phone reception at Invervar is decent but disappears on the ridges.

Outside the SAIS network. No Scottish Avalanche Information Service forecast covers Carn Mairg. SAIS forecasts six areas only — Northern and Southern Cairngorms, Creag Meagaidh, Lochaber, Glencoe and Torridon — and this hill is outside all of them, so there is no avalanche forecast to read for it. In winter, use MWIS Southeastern Highlands for mountain weather, judge snow stability from first principles, and treat any cornice or wind-loaded slope with extra caution.

Best time of year

Best OK Avoid

Getting there

  • Glasgow2h 50m
  • Edinburgh2h 3m
Parking: NN666483

OS maps: OS Landranger 42, OS Landranger 51

Mobile signal: Reasonable signal at the Invervar car park in Glen Lyon. Signal thins beyond 800m. Grab maps before the journey up Glen Lyon.

Current conditions

Daylight Today

14h 46mwalking daylight
Sunrise
06:31
Sunset
19:59
Civil dawn
05:52
Civil dusk
20:38

NOAA Solar Calculator · 7 September 2026

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Carn Mairg — common questions

Is Carn Mairg a hard climb?
Carn Mairg is rated 4/5 (challenging) on the OutdoorSCOT scale. The standard route covers about 17km with 918m of ascent and takes most walkers 5-8 hours. Terrain: The Invervar Burn path is firm peaty track for the first kilometre, then deteriorates onto open hillside.
How prominent is Carn Mairg?
Carn Mairg has 467m of topographic prominence — the height of its summit above the highest col connecting it to higher ground.
Where should I park to climb Carn Mairg?
Standard parking is at NN666483. Check the parking grid reference on an OS map before travel; informal laybys can fill on summer weekends.
When should I climb Carn Mairg?
The standard good-weather months for Carn Mairg are May, June, July, August, September, October. Outside those months, expect winter conditions on the high ground — full mountain kit, navigation skills, and a check of the SAIS avalanche forecast for the relevant region.
Can I bring my dog up Carn Mairg?
On a lead only — the route crosses ground with livestock or nesting-bird interest.
What's mobile reception like on Carn Mairg?
Reasonable signal at the Invervar car park in Glen Lyon. Signal thins beyond 800m. Grab maps before the journey up Glen Lyon.
Is Carn Mairg safe in winter?
A long winter ridge traverse. The broad mossy summits drift deeply but offer few avalanche-prone slopes. The two deep bealachs collect wind-blown snow and can be tiring underfoot. Each of the four tops develops consistent cornicing along its northern flank. The Glen Lyon road is a narrow single-track route prone to drifts. Phone reception at Invervar is decent but disappears on the ridges.

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