Glyder Fawr

Glyder Fawr

Glyder Fawr is the highest summit in the Glyderau in Eryri (Snowdonia). Its surveyed height is 1000.9 m, commonly rounded to 1,001 m, with 642 m of prominence. The summit is a rock tor on an extensive, broken-rock plateau. The source summit grid reference is SH 64246 57956.

Terrain and geology

Approaches range from steep mountain paths and loose scree to exposed scrambling. On the plateau, boulders and irregular rock make progress slow and navigation difficult in cloud.

The regional geology includes Ordovician volcanic and sedimentary rocks. A British Geological Survey sample from Glyder Fawr’s southern flank is ash-flow tuff; the mountain should not be described as uniformly granite. Glaciers shaped the surrounding cwms and ridges, and weathering and rockfall contribute to the rock-strewn landscape.

Choosing an approach

These summaries describe route choices rather than turn-by-turn navigation. Use a current map and a complete route description, including the descent.

• From Ogwen, the usual Cwm Idwal approach passes Llyn Idwal and climbs the steep path beside Twll Du (Devil’s Kitchen) to Llyn y Cwn. Short hands-on sections and a potentially difficult stream crossing precede the loose climb to the summit. The BBC’s 2017 return itinerary is approximately 4.7 miles (7.6 km), with five hours suggested. Conditions and individual pace can require longer.
• From Pen-y-Pass, a southern approach starts beside the youth hostel and climbs above Llyn Cwmffynnon. Parts are indistinct or pathless. This is separate from Yr Wyddfa’s Miners’ Track and Llyn Llydaw, which are on the other side of the pass.
• A Tryfan combination includes scrambling on its South Ridge and returning to Bwlch Tryfan before continuing towards Glyder Fach and Glyder Fawr. Choose and verify the connecting route and descent in advance. Bristly Ridge is a separate scrambling option. This combination is not a simple ridge walk suitable for every walker.
• From Pen-y-Gwryd, a circuit can use that valley’s Miners’ Track to Glyder Fach, cross west to Glyder Fawr, then descend south to Pen-y-Pass and return by the linking footpath. Careful navigation is needed on the summit plateau and descent.
• From Capel Curig, a long eastern traverse crosses Gallt yr Ogof and Y Foel Goch before Glyder Fach and Glyder Fawr. Boggy ground and poor visibility can slow progress. Plan the descent and transport or the additional return distance.

Y Gribin is another scrambling approach to the plateau. It should not be confused with a straightforward walking descent. Route difficulty varies substantially; no single distance or time describes all ascents of Glyder Fawr.

Views and nearby summits

In clear weather the mountain offers views towards Yr Wyddfa and Crib Goch across the Llanberis Pass, along the Glyderau and north towards the Carneddau. Tryfan lies north-east of Glyder Fawr. Nearby Glyder Fach is 994.3 m and Tryfan is 917.5 m in DoBIH v18.6, conventionally rounded to 994 m and 918 m respectively. The Cantilever Stone is associated with Glyder Fach, not Glyder Fawr’s summit.

Access and facilities

The Ogwen Centre is a northern starting point with limited paid parking. Eryri National Park Authority information checked on 15 October 2026 lists the T10 stopping at Ogwen and Bws Ogwen services from Bethesda, so Bethesda is not the nearest bus stop to the mountain’s northern approach. The Centre lists drinks, snacks and toilets; check opening arrangements before relying on them.

Southern routes can start from Pen-y-Pass or Pen-y-Gwryd. Check current Pen-y-Pass parking and booking rules and the Sherpa’r Wyddfa timetable. Plan the last return service and do not rely on an old guide’s parking or bus details. Avoid obstructing roads and respect parking restrictions.

Safety

Loose scree, wet rock, awkward boulders and steep drops demand care. In cloud, navigation errors can lead onto cliffs. Identify the descent before leaving the summit and do not follow a direct line towards a visible lake or valley. Strong winds, snow and ice increase the seriousness of both paths and scrambling routes; winter equipment requires the skills to use it.

Carry a map and compass and know how to use them, alongside appropriate clothing, waterproofs, food, water, a torch and a charged phone. Leave your route and expected return time with someone. For a mountain emergency call 999, ask for Police, then Mountain Rescue.

Name and history

Glyder Fawr is commonly explained as “big heap of stones”, with Glyder linked to gludair/cludair and fawr meaning big. Glyderau is the plural form. Below the mountain, Cwm Idwal became Wales’s first National Nature Reserve in 1954 and is associated with Charles Darwin’s geological investigations. Unspecified summit folklore is not presented as established history.

Sources

Checked 15 October 2026. DoBIH v18.6, record 1967, provides the summit data; its record revision remains 15 November 2016. Route summaries were checked against BBC Weatherman Walking, Walking Britain, UKHillwalking, 10Adventures and Walk up Yr Wyddfa Snowdon. Access and facilities were checked against Eryri National Park Authority; landscape and history against the National Trust, British Geological Survey, GeoMôn and Geoscience Wales. Full URLs and audit decisions are recorded in Comments.