Ben Oss

Ben Oss, at 1,029 metres, is a rugged and substantial mountain in its own right, though it inevitably suffers by comparison with its far grander neighbour Ben Lui, which dominates the view from its summit.

Almost all walkers reach Ben Oss from Beinn Dubhchraig, descending that mountain's ridge past a series of small lochans before dropping down rockier ground to the Bealach Buidhe, overlooking Loch Oss. A tiny cairn marks the point to leave the clearer stalkers' path here, following a fainter route up a grassy slope that becomes better defined as it climbs to Ben Oss's north-eastern top. A short descent to a minor bealach precedes the final, easier ascent along a well-defined ridge just west of south, with a good path leading to the summit cairn — from where Ben Lui appears, in the words of one regular visitor, "nothing short of magnificent."

The return retraces the route back over the north-eastern top and down to the bealach with Beinn Dubhchraig, requiring a reascent of that mountain's ridge since no safe direct descent exists from the connecting bealach.

The combined round taking in both Ben Oss and Beinn Dubhchraig from Dalrigh is around 18-19 kilometres with substantial ascent, typically eight to ten hours; very fit parties sometimes extend the day to include Ben Lui itself, making for an exceptionally long but manageable traverse of all three Munros.

The ascent path to Ben Oss is often only intermittent and can be genuinely hard to follow, particularly in mist, and the broad, undulating ridges throughout this group demand confident navigation — this is not a mountain to underestimate despite being overshadowed by its neighbour.

The Dalrigh car park is free but can be busy; Tyndrum has both rail stations nearby, around 2.5 kilometres away on the West Highland Way.