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Eryri: Ffestiniog and the MoelwynionMoelwyn Mawr and Llyn Stwlan
Up past the high dam of the Ffestiniog pumped storage scheme onto a shapely summit, with quarry ruins and one of the best views of Eryri from the south.
- Distance
- 5.0 mi / 8 km
- Time
- 4 hr
- Ascent
- 650 m
- Difficulty
- Strenuous
- Shape
- Circular
Where it is
The circle shows the general area, not the exact start. Use the directions link below to get to the car park itself. Contours and paths shown are OpenTopoMap, drawn from OpenStreetMap data.
The route
The old dam road climbs from Tanygrisiau to Llyn Stwlan, then paths continue onto Moelwyn Mawr. A circuit is possible over Moelwyn Bach or by dropping to the Croesor quarry track.
Worth knowing
- Stwlan dam is the upper reservoir of Britain’s first pumped storage scheme. The water level moves a great deal.
- Quarry levels and shafts are scattered over these hills. Keep to the paths.
- One of the best places to see the whole Snowdon massif from the south.
What you’ll see
The dam and reservoir, Rhosydd and Croesor quarry ruins, and Cnicht’s pyramid nearby.
Background
Ffestiniog power station opened in 1963, pumping water uphill at night and releasing it at peak demand. The slate quarries around it closed decades earlier.