Bidein a' Ghlas Thuill (An Teallach)

Bidein a' Ghlas Thuill, at 1,062 metres, is the highest summit of An Teallach — "The Forge" — widely regarded as one of the most spectacular and dramatic mountains in Britain, in the remote north-west Highlands near Dundonnell.

The route starts from a layby on the A832 at Corrie Hallie, following a track up wooded Gleann Chaorachain past a waterfall onto open ground, then a cairned path towards Coir' a' Mhuilinn. From here the route climbs steeply and roughly onto Sròn a' Choire, giving the first proper view of the mountain's two Munro summits ahead. Beyond a col paved with flat sandstone slabs, a worn path climbs steeply up scree and boulders to the trig point on Bidein a' Ghlas Thuill's summit — the best viewpoint on the whole mountain, looking directly across the stupendous void of Coire Toll an Lochain to Sgùrr Fiona and the Corrag Bhuidhe pinnacles, widely considered one of the most impressive sights in the Scottish mountains.

Those wanting only the two Munro summits continue south-west along the ridge to Sgùrr Fiona and return by the same route; those undertaking the full ridge traverse continue over the pinnacles beyond, a serious scramble requiring a good head for heights.

The there-and-back route taking in both Munros is around 16-18 kilometres with around 1,400-1,550 metres of ascent, typically six to eight hours.

An Teallach demands genuine respect — even the "easier" there-and-back route to the two Munros involves steep, exposed ground and should only be attempted in good visibility, since navigation on the upper mountain in cloud is notoriously difficult; the full ridge traverse beyond Sgùrr Fiona is a different proposition entirely, with the crux section south of Corrag Bhuidhe graded Difficult in rock-climbing terms.

Parking at the Corrie Hallie layby is free; there is no public transport to the start.