At a glance
Llyn Morwynion is a remote mountain lake above Blaenau Ffestiniog, reached through the extraordinary industrial archaeology of the slate quarry landscape. Associated with a Mabinogion legend, set in a basin of worked rock and wide sky — a destination for experienced walkers who want wildness, history, and very few other people. Allow 3–5 hours return.
About Llyn Morwynion
Above Blaenau Ffestiniog, the landscape changes character as you gain height. The town itself — slate-grey, direct, unapologetic — gives way to the quarry workings that produced it: the vast inclines down which loaded wagons once descended by gravity, the platforms where dressing sheds stood, the lakes and ponds that provided water for the industrial processes, the spoil heaps rising to a horizon that is entirely composed of waste slate. To walk through this is not to walk through a ruin in the conventional sense but through a record of extraordinary scale and effort, spread across a mountain landscape that absorbed the industry and has been absorbing it slowly back into itself ever since.
Llyn Morwynion sits within this landscape at around 380 metres, enclosed on three sides by the spoil and ridge that form its basin. The lake is associated with one of the older Welsh mythological narratives — the fourth branch of the Mabinogi, which locates in this high ground the events surrounding Blodeuwedd and the tragic arc of Lleu Llaw Gyffes. The maidens of the tale drowned here, according to the tradition, while fleeing in terror. It is the kind of association that becomes more vivid, not less, when you are standing at the lake's edge in low cloud with no other human presence visible in any direction.
The walk from Blaenau is a full half-day undertaking on ground that demands attention: rough quarry tracks give way to pathless terrain, the spoil heaps are vast and occasionally unstable at their margins, and the transition from the industrial zone into the more natural upper basin happens gradually rather than at a single clear threshold. The reward is a lake that is genuinely wild — not managed, not signposted, not described in most guidebooks — set in a landscape of dual character that nowhere else in North Wales quite replicates. Slate country and mountain country, industry and myth, ruin and persistence: Llyn Morwynion carries all of it.
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Frequently asked questions
Llyn Morwynion sits in a high mountain basin above Blaenau Ffestiniog, surrounded by the spoil heaps and abandoned workings of the slate quarry industry that defined the area from the 18th to 20th centuries. The lake is at approximately 380 metres and is reached by a walk of 2–3 hours from Blaenau Ffestiniog through the extraordinary landscape of worked and discarded slate that extends above the town.
The name Llyn Morwynion translates as "lake of the maidens" in Welsh. The lake is associated with a legend from the Mabinogion cycle — the story of Blodeuwedd, the woman made of flowers, and the warriors who fought over her. According to the tale, the maidens accompanying Blodeuwedd drowned in this lake while fleeing in fear. The legend gives the lake a resonance in Welsh mythology that adds cultural depth to an already compelling landscape.
The approach to Llyn Morwynion is a serious mountain walk through one of North Wales's most distinctive landscapes. The route passes through the active and abandoned quarry zones above Blaenau Ffestiniog — a terrain of vast slate tips, ruined buildings, and unexplained machinery remnants. The industrial archaeology is as interesting as the natural landscape. The lake itself sits in a relatively sheltered basin with views south towards the Rhinogau and west towards the Moelwynion.
Wild swimming in Llyn Morwynion is possible and has been done by experienced open-water swimmers. The water is clean mountain tarn water, cold at all times of year. The remote location means swimming should only be undertaken by those with appropriate experience and never alone. There are no facilities, no rescue services, and no other people at the lake in most conditions. Those who do swim here find it a deeply atmospheric experience.
The landscape above Blaenau Ffestiniog is one of the most extraordinary industrial environments in Britain — a vast accumulation of slate spoil, ruined inclines, tramway tracks, and abandoned processing buildings extending across several square miles of mountain terrain. The Llechwedd and Oakeley quarries at their peak employed thousands of workers and produced slate that roofed Victorian Britain. Walking through the landscape today involves navigating a spatial record of industrial history on a scale that no museum could contain.
The walk to Llyn Morwynion is moderately serious — the terrain is rough, the navigation requires attention, and the quarry landscape demands care around edges and unstable ground. It is suitable for experienced walkers with appropriate footwear and clothing. A map and compass or GPS are advisable. Allow 3–5 hours for a return walk from Blaenau Ffestiniog including time at the lake. The ground can be wet and slippery in poor weather.