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Adventure Travel

Snowdonia National Park, Wales: Glyder Slate Quarries

This 9.6-mile scrambly route threads between Glyder Fawr and Glyder Fach before wandering along treeless tundra and descending through a massive, abandoned slate quarry.

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Only have time for one hike? Make it here, in the epicenter of trekking and mountaineering in Wales. Between 1905 and 1909, Mallory earned his climbing stripes here while on university vacations. Eventually, like Hillary in later years, he trained for Everest expeditions by scaling Snowdonia’s peaks in brutal winter conditions. Of course, you don’t need to be an aspiring alpinist to see the best of the park—though we recommend you do it spring through fall.
The name Glyders comes from a Welsh word meaning “pile of stones,” which hardly does justice to the striking rock formations atop this range of nine jagged summits that rise 2,000 vertical feet above the valleys below. The route threads between Glyder Fawr and Glyder Fach, the two highest peaks, before wandering along treeless tundra and descending through a massive, abandoned slate quarry. End at Llanberis, a mountain town set lakeside beneath Dolbadarn Castle.
From the Birmingham Outdoor Education Centre at the foot of Llyn (Lake) Ogwen, climb southeast up the ridge of Y Cribn, which quickly takes you to the high plateau between Glyder Fawr (3,278 feet) and Glyder Fach (3,261 feet). Most hikers do this route in a day, with good reason: Wind routinely rips across the exposed ridge at a tent-shredding 40 mph (and dispersed, or “wild,” camping is frowned upon inside the national park). Follow the path west along the ridge, over Glyder Fawr, and continue as it wraps northwest. Otherworldly natural rock sculptures dot the ridgeline, and the terrain drops away precipitously on either side, making this a hike you’ll want to linger over.
After a descent past the pond of Llyn y Cwn, and one more climb, the path traverses downward on sheep trails to break out atop the 19th-century Dinorwic slate quarries. The 700-acre complex of cliffs, ponds, tunnels, and ruins, including what was once the world’s largest man-made cavern, offers an intriguing—and oddly scenic— glimpse into local history. After the descent, a .7-mile walk takes you into downtown Llanberis. Pete’s Eats is the local hotbed for posthike feeding. Don’t miss their map and guidebook lounge on the second floor; it’s a mountainlover’s library for researching peaks and treks from Wales to the Himalaya.
-Mapped by Steve Howe

Trail Facts

  • Distance: 15.5



Location: 53.123354, -4.019296

Park in the lot located across the road from LLyn (Lake) Ogwen. Walk west.


Location: 53.123364, -4.019663

Turn left at the Birmingham Outdoor Education Centre’s Ogwen Cottage.


Location: 53.121244, -4.016479

Bear left (southeast) off the main trail, and climb a faint path through cliffs to Llyn (Lake) Bochlwyd.


Location: 53.11537, -4.011179

At Llyn Bochlwyd, follow the path south to the black buttresses above. Climb and scramble south via the line of least resistance.


Location: 53.104592, -4.017091

At the summit of Y Cribyn, continue south.


Location: 53.103317, -4.01649

Turn left at the junction and head east to Glyders Pass.


Location: 53.103539, -4.014441

Glyders Pass: Stop for views of Llyn Bochlwyd and Castle of the Winds.


Location: 53.099194, -4.019306

Decent bad weather tent site with good drainage and sheltering boulders.


Location: 53.0991, -4.018347

Decent campsite in stormy or windy weather.


Location: 53.103336, -4.01641

On the return trip, continue straight at this junction. Head west along the broad ridge to Glyder Fawr.


Location: 53.101658, -4.028108

Crest the 3,278-foot summit of Glyder Fawr, then bear right and descend Glyder Fawr’s north slopes.


Location: 53.104792, -4.035665

Descend scree, then bear left/west onto the trail that skirts the large lake at Llyn y Cwn. Ahead: Continue north past the lake along the broad plateau of Y Garn.


Location: 53.10664, -4.038838

Bear right, heading north.


Location: 53.109452, -4.04048

Bear left at Y-junction and follow the ridgeline trail to a massive cirque just south of Carnedd y Filiast. Look south for views toward the dark ridges of Snowdon and Tryfan.


Location: 53.130989, -4.054583

Trail sweeps left/west to the ridgeline of Elidir Fawr, with views north to the Marchlun Mawr Reservoir.


Location: 53.132792, -4.06426

Junction: Bear left/southwest for a descending traverse; follow sheep trails across gullies and rocky bands.


Location: 53.128002, -4.072473

Follow sheep trail through easy rock bands.


Location: 53.12432, -4.078932

Intersect a pronounced trail and continue southwest.


Location: 53.123897, -4.079728

Leave trail and traverse across rock fields. Hike towards the ridge crest that rises to the southwest.


Location: 53.120237, -4.087977

Dinorwic Slate Quarries. Bear right across top of tiers.


Location: 53.121355, -4.093193

Pass the ruins of a slate cutting shack.


Location: 53.123145, -4.095671

Pass more slate quarry ruins. The building on the right was a steam boiler power plant.


Location: 53.124991, -4.100521

Skirt the Australia Mine, once the world’s largest pit.


Location: 53.120344, -4.108774

Walk past the Anglesey Barracks Two (worker housing).


Location: 53.118839, -4.112344

The route ends at the parking lot beside the dam at LLyn (Lake) Peris. Downtown LLanberis is one-half mile southwest, across the dam.

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