The finest ridge traverse on the Scottish mainland: two Munros linked by about 600 m of Torridonian sandstone pinnacles, undercut on the Toll an Lochain side so the exposure is total. Taken direct it is the hardest of the mainland big three — harder than the Aonach Eagach, harder than Liathach — but almost all of that difficulty is optional, because a bypass path runs the length of the pinnacles on the west flank.

An Teallach 1062 m — full traverse

Grade 3 scramble direct (Grade 2 on the bypass) / 15.50 km / 8:30 h / 1442 m ↗

Plan

  1. From the Corrie Hallie layby, take the track SW, then the Shenavall path, then up the rough SE flank of Sail Liath.
  2. North along the whole crest: Stob Cadha Gobhlach, the Bad Step, the Corrag Bhuidhe pinnacles, Lord Berkeley’s Seat, Sgùrr Fiona, Bidein a’ Ghlas Thuill.
  3. Off the NE end over Glas Mheall Liath and down Coir’ a’ Ghiubhsachain back to the car.

Go south to north. It means you climb the Bad Step instead of down-climbing it, which is the whole point: Walkhighlands notes the final descent off Corrag Bhuidhe is a graded rock climb and the scene of several fatal accidents, and that they happen mostly in descent. The BMC says that when Dundonnell MRT is called to An Teallach it is almost always scramblers stuck at the Bad Step.

The ridge, in order

  Height Character
Sail Liath 954 m Rounded, quartzite, no scrambling — the way on
Stob Cadha Gobhlach 960 m Sharp top, rough walking, still non-technical
The Bad Step — The crux. Two short pitches of ~12 m
Corrag Bhuidhe pinnacles 1040–1049 m ~600 m of sustained sandstone scrambling
Lord Berkeley’s Seat 1030 m Overhanging pinnacle leaning over the void
Sgùrr Fiona 1060 m Munro
Bidein a’ Ghlas Thuill 1062 m Munro, and the true summit

The Bad Step sits at the start of the Corrag Bhuidhe Buttress, reached after Sail Liath, the Cadha Gobhlach col and Stob Cadha Gobhlach. Two short pitches of about 12 m on rippled sandstone — frictionful, but with a sparsity of positive holds. There are three ways at it: direct (Grade 3), an easier middle line, or the flanking bypass. Steve Fallon puts the direct ascent or descent of Corrag Bhuidhe at rock-climbing Difficult, with easier ways just west of the direct line. The BMC says it takes a basic scramblers’ rack.

The bypass path runs on the west / south-west flank just below the crest, starting from the foot of Lord Berkeley’s Seat, and rejoins the ridge beyond Corrag Bhuidhe Buttress. It removes Lord Berkeley’s Seat, the pinnacles and the Bad Step, and drops the day to about Grade 2. Wikipedia’s caveat is worth heeding: it “is eroded in some places and should not be regarded as an easy option.”

Commitment

  • Escape is only ever to the south-west. The Toll an Lochain side is the cirque headwall, several hundred metres of cliff.
  • The bypass makes this technically harder but strategically less committing than the Aonach Eagach.
  • Getting off the mountain part-way: a very steep, loose path drops from the Cadha Gobhlach col to Loch Toll an Lochain, and past the pinnacles you can drop north from Bidein into Glas Tholl.
  • No fixed gear of any kind — no pegs, no abseil stations, no cables. British practice is to solo this; guides rope clients over the pinnacles.
  • Rock is Torridonian sandstone, with quartzite caps on Sail Liath and Glas Mheall Liath. Sources disagree on how the sandstone behaves wet — some call it grippy in the rain, trip reports say otherwise — but everyone agrees the quartzite goes greasy.
  • Calibration: British Grade 3 is roughly alpine PD, with the Bad Step direct feeling PD+/AD− for its few metres.

Logistics

Which round

The 15.5 km figure is only valid for the true one-car round: Corrie Hallie → Sail Liath → full crest → out over Glas Mheall Liath → down Coir’ a’ Ghiubhsachain. The sting is the last part of that descent: a nasty boulder field, then steep vegetation weaving between crag bands, and a final section reported as genuinely horrendous.

Other published versions are longer and several do not finish where you parked:

Source Start Distance Ascent Time
UKHillwalking Corrie Hallie 15.5 km 1442 m 8:30
LFTO / Trail Corrie Hallie 20 km 1370 m —
Walkhighlands Dundonnell 20 km 1415 m 9–10 h
Get Lost Mountaineering Corrie Hallie 26 km — 11–13 h

A Glas Tholl or Dundonnell finish leaves 3.5–4 km of A832 tarmac back to Corrie Hallie — second car or a bike.

September

Daylight runs from about 14 h at the start of the month to 11 h 35 by the end, so the 8:30 h round has margin but not a lot if the ridge goes slowly. No old snow — An Teallach holds none. Midges collapse through the month, making late September a good window. Wet-day probability sits around 45%, and this is a route you want dry.

Notes

  • Ullapool for the full range of shops, fuel and food.