Beinn Mhanach

Beinn Mhanach, at 953 metres, is a dome-shaped, unspectacular Munro — its Gaelic name meaning "monks' mountain," said to derive from a long-vanished monastery once used by Clan MacGregor at its foot. Despite its plain profile, one of the remoter peaks of the Southern Highlands, it carries a genuine feeling of seclusion, and the approach up Auch Glen is very enjoyable.

The route starts from limited parking on the east side of the A82 near the Loch Lomond National Park boundary sign. A track heads north with fine views of Beinn Dòrain ahead, joined by the West Highland Way before turning right at a crossroads to follow the Allt Kinglass. The track crosses a bridge and passes beneath the railway viaduct into Auch Glen, fording the river several times — up to seven or more crossings depending on the exact route and water levels, generally shallow and manageable in normal conditions but potentially impassable in spate. Beyond the farm buildings at Ais an t-Sìdhean, an unrelenting but grassy and mostly firm ascent leads to the summit, with restricted views owing to the higher peaks all around, though Beinn a' Chreachain to the north looks particularly impressive, and a short detour along the ridge reveals most of Loch Lyon.

An alternative, slightly shorter approach starts from Achallader Farm, climbing Coire Achaladair to Coire Daingean and the bealach before traversing slopes to Lon na Cailliche — several regular visitors report this route being wetter underfoot than the Auch Glen approach, despite its shorter distance.

The round trip from the A82 via Auch Glen is around 21.7 kilometres with roughly 750 metres of ascent, typically seven to eight hours; the extremely fit sometimes include Beinn Mhanach as a demanding detour from a wider traverse of the Bridge of Orchy Munros.

The multiple river fords along Auch Glen are the defining hazard of this route — several are recorded as becoming genuinely impossible after heavy rain, and walkers should check conditions and carry a realistic contingency plan; this is remote terrain with no paths on the mountain itself, requiring full navigation skills.

Parking near the Auch Glen turnoff on the A82 is free but very limited on a grass verge; buses run along the A82 past the start.