Cadair Idris, Mynydd Moel and Craig Lwyd Circular
You get the full horseshoe around one of Snowdonia's most dramatic cwms rather than a straight there-and-back to the summit, so the mountain's best feature - the cliff-ringed bowl at its heart - is in view for most of the route.
Effort: Shorter distance, serious climb
Underfoot: Open fell or rough terrain
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A 15.6km horseshoe around Cadair Idris from the Tal-y-Llyn side, taking in Craig Lwyd, Mynydd Moel and the summit of Penygadair itself, with 582m of climbing above the cliffs of Cwm Cau.
You get the full horseshoe around one of Snowdonia's most dramatic cwms rather than a straight there-and-back to the summit, so the mountain's best feature - the cliff-ringed bowl at its heart - is in view for most of the route.
The route
This circuit takes the long way round Cadair Idris, climbing onto the ridge at Craig Lwyd before following the rim of Cwm Cau across Mynydd Moel to the true summit, Penygadair, at 893m. From there the ridge continues around the horseshoe with Tal-y-Llyn lake visible below for much of the descent. It's a proper mountain circuit rather than a single out-and-back, and the 1044m of climbing is spread across a ridge line that rarely lets up.
Cwm Cau
The reason to do the full horseshoe rather than the shorter paths up Cadair Idris is Cwm Cau, the huge cliff-ringed bowl that sits at the mountain's heart. Running the rim of it, with Llyn Cau dark in the bottom, is one of the better mountain moments in Wales, and it's the kind of terrain that photographs badly and feels enormous in person.
Local legend
Cadair Idris translates as the chair of Idris, a giant said to have used the mountain as a seat, and local folklore holds that anyone who sleeps on its slopes overnight wakes up either a poet or mad. Whichever way that goes for you, the summit shelter on Penygadair is a welcome stop on a rough day, with views out over Cardigan Bay when the cloud lifts.
Getting it right
The ridge is well defined and mostly on clear paths, but the ground close to Cwm Cau's rim drops away sharply, and cloud on this side of the mountain comes in fast off the sea. Give yourself a proper weather window rather than chancing it, and treat the exposed sections above the cwm with the same respect you'd give any mountain edge.
Getting there
Minffordd sits on the A487 between Machynlleth and Dolgellau, well south of the busier approaches to Snowdon itself, so this side of the national park stays noticeably quieter even in peak season. That's worth factoring in if you're chasing solitude on a clear day: you can run the full horseshoe here without the queues that build up on the more famous mountain in the north.

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The ridge above Cwm Cau has genuine drops close to the path, and cloud rolls in quickly off Cardigan Bay with little warning. The horseshoe has no easy bail-out once you're committed past Craig Lwyd.
Summits on this route
Safety on this route
- No signal? Text 999 — pre-register first: text register to 999
- Tell someone your route and expected return time before you head out
Leave No Trace
- Leave nothing but footprints, take nothing but memories.
- Please respect the countryside and all its inhabitants.
- Dogs on leads near livestock, and around ground-nesting birds from March to July.
- Gates as you find them — open or closed, leave it that way for the farmer and the next runner.
- Take it all home — wrappers, peel, tissue, the lot. It doesn't count as biodegradable if you can still see it.
- Stick to the path where the ground either side is wet, planted, or nesting habitat.
Common questions
- Most runners complete Cadair Idris, Mynydd Moel and Craig Lwyd Circular in 2 hours 35 minutes to 3 hours 35 minutes, depending on pace and conditions.
Run by us
Jason Millward has run this route and written it up from the ground. How we check routes
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Runner reports
Nobody's logged a run here yet. If you get out on it, a few lines about how it went helps the next person plan their day.
Races on this ground
All Eryri (Snowdonia) races →Races starting within 20 km of the Cadair Idris, Mynydd Moel and Craig Lwyd Circular start, nearest first. If you are entered for one, this route is the rehearsal.
6
Jul
2028

MTC Gelert
Sandbanks Hotel, Marine Parade, Barmouth, LL42 1NE · Ultra Running Ltd · 8 miles away
Barmouth to Llanidloes, 47.0 miles.
Not open yet
19
Jun
2027

Ultra Wales
Coed-y-Brenin, Gwynedd · GB Ultras · 10 miles away
Fifty-one miles out of Coed-y-Brenin.
EXPERT
Entries open


