Often lauded as one of Scotland's most beautiful mountains, Ben Lui cuts a striking figure, rising high over its immediate neighbours. Its best side is to the east, where the graceful twin peaks and the symmetrical scoop of Coire Gaothach are seen to full effect. It's a long walk-in down the Cononish glen, but with Ben Lui looming ever larger ahead the anticipation mounts all the way. In winter conditions Coire Gaothach and its sharp ridges look almost Alpine, and the various ascent routes on this flank of the hill all need a degree of mountaineering competence. I've covered the least demanding option here - it's good for summer too. Ben Lui alone makes a great round, but it's better still combined with the adjoining Munros Ben Oss and Beinn Dubhchraig, nice peaks in their own right. For the very keen there’s a fourth Munro too, Beinn a’Chleibh, though that means an untidy detour or a logistically tricky linear route.
metres / Distance
NN3440029106 From the car park follow the track signed for Ben Lui, west past two houses. Cross a bridge over a burn, pass a turnoff signposted for the West Highland Way, then go under the railway. The track now continues a long way up the glen between forestry plantations and the broad River Cononish, entering the Ben Lui National Nature Reserve. Pass through Cononish farm and below the gold mine by the prominent waterfall of Eas Anie. The track then traverses the southern flank of Beinn Chuirn before descending to the Allt an Rund, where it ends.
NN2813527362 Cross the burn and join an eroded trail running steeply uphill beside the Allt Coire Ghaothaich to pass between the twin peaks framing the mouth of Coire Gaothach. From the sloping corrie floor climb quite steeply west (care needed in winter conditions) to gain a little saddle between the minor top of Stob Garbh and Ben Lui itself. Here turn left up the defined ridge crest leading to the mountain's northwest top. A broad summit ridge runs from here to the main peak; the edge overlooking the corrie may be heavily corniced.
NN2662626284 Descend the mountain's southeast ridge, steep at first but soon shallower angled, to reach the low peaty bealach at the head of Coire Laoigh. An intermittent path now makes a long climb through rough hummocky ground (good navigation is helpful in mist here) to the cairn on top of Ben Oss.
NN2875625339 From the summit stay with the high ground down the north-northeast ridge, then bear east over a minor top (spot height 941m). Continue roughly east down to the Bealach Buidhe, which divides Coire Buidhe and Coire Garbh. A path now zigzags quite steeply uphill onto a lochan-scattered shoulder at about 900m. From here a gentler climb east-southeast leads to the top of Beinn Dubhchraig.
NN3077525480 Go briefly down the broad northeast spur, then at roughly the 900m contour trend left into the shallow scoop of Coire Dubhchraig (unnamed on some OS maps). In the corrie join a boggy path downhill beside the Allt Coire Dubhchraig, passing first through pine plantations and then a more open Scots pine wood on the lower slopes.
NN3331528412 Once back down in the Cononish glen, and near the River Cononish, cross a footbridge over the Allt Coire Dubhchraig. Now bear right over wet ground to join a vehicle track. This crosses first the railway, and then an old stone bridge over the River Cononish, to return to the car park.
Terrain: Long easy track in the Cononish glen. It's ideal for bikes if you're just doing Ben Lui, but cycling is pointless if traversing all three mountains. On the hills there are some steep gradients and the odd boggy bit, but paths are generally clear.
Seasonal variations: Ben Lui is a classic winter peak. In snow all ascents on the Coire Gaothach side have a mountaineering feel, and the route described here, the right hand (northwest) skyline of the corrie, is the only option for walkers. Winter climbers might instead do the mountain's steeper East Ridge, or the grand old fashioned Central Gully - both grade I climbs. Watch for avalanche conditions in the corrie, and corniced ridges. The remainder of the route is easier walking, though it's a long way for a short winter day. To maximise daylight on the hills the glen track could be done before dawn.
Done this a couple of times and it's a great route, especially in winter when you can start via Central Gully. I disagree that Beinn a' Chleibh is an 'untidy' detour though - you just return to the col to the SW of Ben Lui and traverse SE to the next col
I agree with you about Beinn 'Chleibh - it's not that much of a detour, and it makes for a very satisfying day. This was my ascent of Ben Lui some years ago, one Easter. I'd driven up from the South for the weekend, and there was a bit more snow than I was anticipating. Top day out. http://www.ukclimbing.com/images/dbpage.html?id=7984