Craig Cwm Silyn

About Craig Cwm Silyn

As the highest point of the celebrated Nantlle Ridge, this rocky summit offers a dramatic contrast between gentle southern slopes and the precipitous northern crags overlooking the Llyfni valley. Reaching this Hewitt rewards walkers with an expansive view spanning the Llŷn Peninsula and the western flanks of the Snowdon massif.

Key Statistics

Find It

Did You Know?

• •The name translates from Welsh as 'The Crag of the Valley of Silyn'. While the exact origin of Silyn is debated, it is most likely a personal name, with the title referring to the deep glacial cirque and the twin lakes, Llynnau Cwm Silyn, lying directly beneath the mountain's north face.
• •The mountain is famous among rock climbers for 'The Great Slab' (Y Llech Fawr), a 100-metre wall of high-quality volcanic rock. It provides some of the best-regarded mid-grade multi-pitch climbing in Eryri, known for its clean lines and superb friction.
• •Most walkers traverse this peak as part of the Nantlle Ridge, a high-level outing often cited as a quieter, more atmospheric alternative to the Snowdon Horseshoe. It marks the transition from the rugged peaks of central Eryri to the softer, greener hills of the Eifionydd district.
• •The summit panorama offers a unique perspective of the Snowdon massif to the east, but the most 'earned' view is to the west; on a clear day, the entire Llŷn Peninsula unfolds, with the peaks of Yr Eifl and the distant outline of Bardsey Island visible on the horizon.
• •Despite its status as a Marilyn and a Hewitt, the summit plateau is so broad and littered with grey boulders that finding the true highest point in a thick mist can feel less like a mountain ascent and more like a very focused search for one specific stone.