Carn Mairg, Carn Gorm, Meall Garbh & Meall na Aighean
Maps 378E, 51; 12 Feb 2005 & 24 Aug 2008

Route: 1500m = 5070' ascent; 11¼ miles; 6-8 hrs

Route: Parking is marked by a phone box in Invervar (Glen Lyon) on the S side of the road, behind which is a small car park, 5yds down the "private road". In Feb 2023 I found this closed with a note about a dangerous tree and so parked on the roadside at NN66374819.
The start of the walk is a few yards west along the road towards the river from the parking. Go through gate at far side of a white cottage, as indicated. The track up the valley has now mostly recovered from work on a hydro scheme.
For some unexplained reason the local estate expects you to follow the route only in a clockwise direction. However, the anti-clockwise direction is probably more pleasant unless the prevailing wind is blowing because of the better path on the eastern end than the western end and because navigation in cloud on Meall na Aighean is also easier that way.
I have included all the three related Munro tops in this walk. Two of them are detours from the natural route round the Munros and can be omitted easily. However, one of these, namely the shapely An Sgorr, is well worth including. It adds a mere 70m of ascent over easy terrain and almost no distance whilst yielding a great view from its position at the head of a valley. There is a lower level path for those wishing to avoid this Top.
The route along the ridge follows boundary fence posts between Meall Garbh and Meall Liath.

Access: The local estate has a very poor reputation regarding access and actively discourages walkers for much of the year with notices, tight restrictions on roadside parking, regular closure of the only parking area, threats, etc. For details see North Chesthill Estate. This can be very problematic if you have left route information with friends and have to change plans in a glen with no connectivity, or you have come hundreds of miles just to tick off these particular Munros and only have maps of this area with you.
The Mountaineering Council of Scotland had some strong words to say about the estate's behaviour in 2015. Other helpful discussions include, for example, one from 2014 on WalkHighlands, another from 2020 also on WalkHighlands and a third from 2021 on “The National”.

Connectivity: There is a good mobile signal two miles or so east of Invervar on the road towards Fortingall.

Weather (12/2/05) Cloud base at around 2500', very strong winds, frequent snow showers, drifting snow. Blizzards! Snow cover down to sea level, drifts up to 3', no firm snow underfoot. (Very slow times for 12/2/05 because of severe weather conditions, compass problems & darkness from 1800.)
Weather (24/8/08) Cloud base around 3000', some tops clear, stiff showers & some drizzle.