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.
Get full access to Outside Learn, our online education hub featuring in-depth fitness, nutrition, and adventure courses and more than 2,000 instructional videos when you sign up for Outside+ Sign up for Outside+ today.
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
Waypoints
GLD001
Location: 53.123354, -4.019296
Park in the lot located across the road from LLyn (Lake) Ogwen. Walk west.
GLD002
Location: 53.123364, -4.019663
Turn left at the Birmingham Outdoor Education Centre’s Ogwen Cottage.
GLD003
Location: 53.121244, -4.016479
Bear left (southeast) off the main trail, and climb a faint path through cliffs to Llyn (Lake) Bochlwyd.
GLD004
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.
GLD005
Location: 53.104592, -4.017091
At the summit of Y Cribyn, continue south.
GLD006
Location: 53.103317, -4.01649
Turn left at the junction and head east to Glyders Pass.
GLD007
Location: 53.103539, -4.014441
Glyders Pass: Stop for views of Llyn Bochlwyd and Castle of the Winds.
GLD008
Location: 53.099194, -4.019306
Decent bad weather tent site with good drainage and sheltering boulders.
GLD009
Location: 53.0991, -4.018347
Decent campsite in stormy or windy weather.
GLD010
Location: 53.103336, -4.01641
On the return trip, continue straight at this junction. Head west along the broad ridge to Glyder Fawr.
GLD011
Location: 53.101658, -4.028108
Crest the 3,278-foot summit of Glyder Fawr, then bear right and descend Glyder Fawr’s north slopes.
GLD012
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.
GLD013
Location: 53.10664, -4.038838
Bear right, heading north.
GLD014
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.
GLD015
Location: 53.130989, -4.054583
Trail sweeps left/west to the ridgeline of Elidir Fawr, with views north to the Marchlun Mawr Reservoir.
GLD016
Location: 53.132792, -4.06426
Junction: Bear left/southwest for a descending traverse; follow sheep trails across gullies and rocky bands.
GLD017
Location: 53.128002, -4.072473
Follow sheep trail through easy rock bands.
GLD018
Location: 53.12432, -4.078932
Intersect a pronounced trail and continue southwest.
GLD019
Location: 53.123897, -4.079728
Leave trail and traverse across rock fields. Hike towards the ridge crest that rises to the southwest.
GLD020
Location: 53.120237, -4.087977
Dinorwic Slate Quarries. Bear right across top of tiers.
GLD021
Location: 53.121355, -4.093193
Pass the ruins of a slate cutting shack.
GLD022
Location: 53.123145, -4.095671
Pass more slate quarry ruins. The building on the right was a steam boiler power plant.
GLD023
Location: 53.124991, -4.100521
Skirt the Australia Mine, once the world’s largest pit.
GLD024
Location: 53.120344, -4.108774
Walk past the Anglesey Barracks Two (worker housing).
GLD025
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.