The Big Walk: Snowdonia Slate Trail

The 83-mile circular Snowdonia Slate Trail takes walkers through a lost world of abandoned quarries, hidden gorges, fairy-tale waterfalls and even a Celtic rainforest.

By Sarah Stirling

Abandoned slate quarry.

A kestrel was brooding over the moor. Before us, pink heather, blushing in the last of the light, sloped down to meet patchwork fields, the grey, pebbledashed village of Y Fron and the sea glittering red beyond. Just west of us, a mini-peak called Moel Tryfan looked eerily primeval, luring us towards its summit, over mossy mounds popping with tiny white heath bedstraw flowers. Welcome to mile 20 of the Snowdonia Slate Trail.

The mountaintop has been quarried into a giant egg cup. Peering over the edge revealed two lakes, shimmering cool turquoise. Amphitheatre-like walkways of purple slate, which once echoed with quarrymen’s hobnailed boots, tower above the water. In places, the industry has left monumental slate pillars. Exploring Snowdonia’s slate-mining heritage feels like stumbling upon lost civilisations.

The celebrated 20th-century Welsh-language author, Kate Roberts, grew up at the foot of Moel Tryfan during the slate heydays of the early 1900s. Her novels reveal a harsh but idyllic lifestyle scraped from the land and the quarries.  A time when heather was gathered for kindling and worn clothes were carefully patched. Kate’s childhood home is now a heritage centre.

I have lived in North Wales for three years and explored it, I’d thought, extensively on foot. However, the new Snowdonia Slate Trail (opened in 2017) was leading me along wild corridors I never knew existed. Paths that slope over the shoulders of forgotten peaks and rise up through lost valleys. Trails that pop out in the region’s most celebrated villages – Llanberis, Beddgelert, Betws-y-Coed – but sneak around the region’s famous peaks; eyeing them up from paths largely overlooked since the quarrymen packed up. Here are some of my favourite sections.

Slate beginnings 

The disused remains of a slate quarry.

The Slate Trail starts at Port Penrhyn, just outside the city of Bangor, where horse-drawn wagons used to disgorge slate into sailing ships for export around the world. Nearby Penrhyn Castle reveals the huge gap in living standards between quarry owners and quarry workers. Perhaps Britain’s finest example of the neo-Norman style, the castle is fairy-tale decadent and, my husband Rob points out, offers tea and cake. Don’t miss the slate bed made for Queen Victoria’s visit, which literally weighs a ton. 

Seven miles further south, from a hillside just outside Bethesda, we get our first good view of some Snowdonian giants: the Carneddau and Glyderau mountain ranges. The scene, though, is dominated by the exposed blue ribs of a mountain in the foreground. Penrhyn, once the world’s largest slate quarry, has eaten into it in square-cut steps. It’s amazing to think that Welsh slate lay hidden under the earth for 400 million years, then, during a few frantic decades of industry, all this was wrested to the surface.

No other stone industry has ever dominated world markets like North Welsh slate did. The mountain quarries here roofed the 19th-century world. Gargantuan amounts of slate were shipped, then the industry collapsed in the 1960s due to the rise of cheaper European slate and mass-produced tiles. Snowdonia has been left scattered with prescient, apocalyptic lost worlds, which are slowly being reclaimed by nature. These otherworldly slate landscapes are the UK’s 2019 nomination for UNESCO World Heritage status: a fitting reminder of the resilience of nature and the short-termism of mankind.

With its dinky stone cottages and strip-fields, the nearby village of Mynydd Llandegai seems little changed since the slate days. The fields are fenced with tombstone-sized slabs of slate, edges worn smooth by rain and speckled with lichen.

Zigzag paths and beckoning water

At mile 12, the route slinks around the green shoulder of a peak called Elidir Fawr and we get a view of its neighbour, the hulking Snowdon massif, with Llanberis village huddled at its feet. The inviting blue water of Llyn Padarn beckons from the valley floor, and a zigzag path leads the way down to the Gallt y Glyn pub.
We detour to walk down Elidir Fawr’s face, which has been quarried into purple galleries that reach almost to its summit. This route was once the morning walk of thousands of hardy, flat-capped men, off to work at Dinorwic Quarry. Nowadays, rust creeps over abandoned machinery, and plants grow from cracks in slate workshops; as if trying to return them to the earth.

In between two villages that time forgot, Croesor and Tanygrisiau, we cross the wildest section yet: a green desert scattered with the ruins of slate communities and echoing with their stories. ‘It’s like discovering Machu Picchu!’ I exclaim. A forlorn chapel stands roofless. At Cwmorthin Quarry, rows of cramped quarrymen’s cottages whistle with draughts. Sometimes whole families lived in these tiny, terraced dwellings. Schoolteacher Mrs Hughes was renowned for travelling up to one quarry near here in a slate wagon and whizzing down in a ‘wild car’ – essentially a skateboard on rollers with a brake – at the day’s end.

At mile 45, Blaenau Ffestiniog is a reminder of the huge waste generated from Victorian slate tile manufacture. For every ton of finished slate, around nine tons of waste were tipped. The slate piles here are human-made mountains that dwarf the cottages. Rogue rhododendrons add splashes of pink to the slopes in spring and summer. These garden and estate escapees shouldn’t be here, either.

The slate layer in Blaenau Ffestiniog isn’t horizontal, as it was further west at Penrhyn and Dinorwic: it plunges on a 30-degree angle. In order to follow the course of these blue veins, the slate here had to be extracted from underground. Over a few decades, Oakeley Quarry grew from a three-man enterprise into the largest underground quarry in the world. It was around 30 floors deep with about 43 miles of connecting tunnels.

The Oakeley family, who owned the quarry, bought and buried a village, Rhiwbryfdir, and a monastery, Mynachlog. Mills were built on top of slate spoils. A story of the time: health and safety standards were low, and eventually huge rockfalls and the family’s fortune both came crashing down.

We pass the village railway station. A few of the old slate railway lines have been restored and reopened, and perhaps the best of these is the Ffestiniog – the world’s oldest narrow-gauge railway – which takes you 13½ miles out to the coast at Portmadog, powered by original, 150-year-old locomotives. We have other plans for 
today, though. A few miles south of Blaenau, we wander down a meadow and emerge in another kind of lost world. Everything is softened with moss. Huge waterfalls plunge into water-carved rock pools. We pause at a strange rock pillar known as Huw Llwyd’s Pulpit after a 17th-century local character who used to converse with spirits here. A red squirrel skitters across the path. This is Cwm Cynfal. 

Next comes the most remote section of the walk: striding across the blanket-boggy back of beyond, a huge expanse of moorland covering central Snowdonia known as the Migneint. 

I gaze around at huge outcrops of cliffs, mountains and ridges that I’ve never seen before, and the hut circles of a partially reconstructed hillfort, Bryn y Castell.

Waterfalls and gorges

We emerge on a forgotten road, which leads us up a valley I’ve never heard of: Cwm Teigl. There is not a car or person in sight. At the top of this road is Cwt-y-Bugail, one of a handful of slate quarries still in operation across North Wales. The contents of the National Gallery were hidden deep in the underground quarries up here during the Second World War. From just outside the quarry I have a Messerschmitt view over the landscape. I can see nothing man-made apart from the slate works.

The Penmachno to Capel Curig section of the walk bursts with high accolades: Swallow Falls is Wales’s highest continuous waterfall, and the Fairy Glen is the region’s prettiest gorge. Approaching Betws-y-Coed at mile 63, we peek at the Roman Bridge, hidden in a green glen and festooned with drooping ivy. It’s not actually Roman, but it is an ancient packhorse bridge. Further on, we reach the 50-foot drop of Conwy Falls. A fish ladder has been built here to help leaping salmon return to their ancestral breeding grounds. Next, we reach the Fairy Glen, a fragment of Celtic rainforest where cascades and rapids are channelled into a narrow ravine cloaked in greenery. 

It’s a dreamy landscape with light pouring through the trees, and we decide to pause here for a swim. These remnants of ancient woodlands are a reminder of how most of Wales would look if it wasn’t constantly grazed by sheep.

In Betws-y-Coed, a chocolate-box village full of historic bridges, restaurants and outdoors shops, we plump for Welsh tapas in the big windows at Olif, then continue past Miners Bridge – yet another gorge beauty spot, which was crossed by the quarrymen on their way to work in the Gwydyr Forest – 
to Swallow Falls. Here, a chasm projects a spectacular waterfall among beech, conifer and birch trees. A narrow but safe path clings to the cliffs above the swirling torrent.

At mile 72, as we descend towards Capel Curig, views of Snowdon, Moel Siabod, the Carneddau and the Glyderau range open up, heralding a change in scenery. The final section is a beautiful stretch through the Ogwen and Nant Ffrancon Valleys; Tolkienesque, with huge green mountainsides, heather sprouting from crags and the mile-long Ogwen lake. The valleys are little developed, making them a haven for all kinds of birds and even otters. 

I can’t wait to walk this final stretch, but first there’s an inn, Bryn Tyrch, which offers great food and board – and views of Moel Siabod. Nos da, as they say round here... goodnight.  

Walk it!


The circular 134km/ 83-mile Snowdonia Slate Trail starts 
at Port Penrhyn in Bangor and ends at Bethesda. It typically takes seven days to complete comfortably.


OS Explorer OL17 and OL18; The Snowdonia Slate Trail (£12.99, Rucksack Readers).


Plenty of choice, especially in Bangor, Bethesda, Llanberis, Beddgelert, Llan Ffestiniog, Penmachno and Capel Curig.

Further info,

‘One of the best moments walking the trail was setting up my final camp with a view over the Ogwen Valley and the Glyders on one side and the sunset behind the slate tips of Penrhyn Quarry on the other. Snowdonia at its best and an overwhelming feeling of “I made it.”’ 
Paula Renzel, Ramblers Cymru. Read her blog about completing the trail solo.