At a glance
Wales's third-highest mountain group — Glyder Fawr (1,001 m) and Glyder Fach (994 m) — rising above the Ogwen Valley with a shattered high plateau, the famous Cantilever Stone, the Devil's Kitchen below, and sweeping views to Snowdon and the Carneddau.
About the Glyderau
The Glyderau — comprising Glyder Fawr (1,001 m) and Glyder Fach (994 m) — form the third-highest mountain group in Wales, rising steeply above the Ogwen Valley between Tryfan to the east and Y Garn to the west. The plateau between the two summits is one of the most dramatic high mountain landscapes in Britain — a chaotic jumble of enormous frost-shattered boulders, rock spires and slabs at over 950 m.
The mountains are composed of ancient Ordovician rhyolites and ignimbrites — volcanic rocks that have fractured over millions of years into the distinctive angular blocks that give the high plateau its wild character. The twin peaks are typically climbed together on a circuit from the Ogwen Valley, either ascending via Bristly Ridge (a short Grade 1 scramble connecting with Tryfan) or the longer approach via Llyn y Cwn from the Y Garn side.
Below the Glyderau's northern escarpment lies Cwm Idwal — the first National Nature Reserve designated in Wales — with its glacially scoured lake, the crags of the Idwal Slabs (a classic beginner climbing area), and the dramatic cleft of Twll Du (Devil's Kitchen). The cwm is accessible as a 2-hour walk from Ogwen without climbing the full Glyderau, making it one of the finest short walks in North Wales.
What to see on the Glyderau
- The Cantilever Stone — A massive flat slab projecting horizontally from the Glyder Fach plateau — perfectly balanced and supremely photogenic.
- Devil's Kitchen (Twll Du) — The dramatic cloud-filled chasm in the cliff above Llyn Idwal — accessible from the Ogwen Valley without climbing the full plateau.
- Cwm Idwal — The glacial cwm below the Glyderau — a National Nature Reserve with Llyn Idwal, the Idwal Slabs and rich arctic-alpine flora.
- Glyder Fach summit boulders — The summit plateau is a maze of enormous angular blocks creating a natural labyrinth — a striking and other-worldly landscape.
- Views from Glyder Fawr — Clear-day panoramas take in Snowdon, the Carneddau, Tryfan, Anglesey, and on exceptional days as far as Ireland.
Safety information
Welsh mountains demand respect. Conditions can change in minutes — even Snowdon in July sees casualties from inadequate kit and unexpected weather.
Carry: waterproofs, walking boots, warm layer, hat & gloves, OS Explorer OL17 (Snowdonia) or OL18 (Harlech & Bala), 1.5 L water, charged phone, head torch. Check the weather at mwis.org.uk on the morning. In an emergency call 999, ask for Police / Mountain Rescue, give your what3words location. Local team: Ogwen Valley Mountain Rescue Organisation (OVMRO).
Find it on the map
Frequently asked questions
Glyder Fawr is 1,001 metres — the third-highest mountain in Wales after Snowdon (1,085 m) and Carnedd Llywelyn (1,064 m). Glyder Fach is 994 m. The two summits are separated by a short ridge and are usually climbed together in a single circuit.
The Cantilever Stone is a massive flat slab of rock projecting horizontally from the Glyder Fach summit plateau — it looks precarious but is firmly in place. Generations of walkers have had their photographs taken balanced on its end. It is one of the most photographed natural features in the Welsh mountains.
Twll Du (the Black Hole) — known in English as Devil's Kitchen — is a dramatic cleft in the cliff above Llyn Idwal at the base of the Glyderau. Water seeps down from the plateau above, and in misty conditions wisps of cloud drift out of the chasm, hence the dramatic name. Llyn Idwal and the Kitchen are accessible without climbing the full Glyderau — a fine 2-hour walk from Ogwen.
The classic Ogwen circuit ascends via Bristly Ridge (a short Grade 1 scramble) from Bwlch Tryfan, traverses Glyder Fach and Glyder Fawr, then descends via Llyn y Cwn and the Devil's Kitchen path to Llyn Idwal and back to Ogwen. This circuit is 7 miles and takes 5–7 hours depending on pace.
Yes — the classic "Tryfan and Glyderau" combination is one of the finest mountain days in Wales. Ascend Tryfan via the North Ridge (Grade 1 scramble), descend to Bwlch Tryfan, then ascend Bristly Ridge onto the Glyderau plateau, traversing both summits before descending to Llyn Idwal. Allow 7–9 hours for the full circuit.
Glyder Fach is slightly lower (994 m) but has more interesting terrain — the Cantilever Stone, the summit chaos of enormous rock blocks, and the Bristly Ridge approach. Glyder Fawr (1,001 m) is the higher summit with slightly less dramatic immediate terrain but outstanding 360-degree views. Both are typically climbed on the same circuit.