The western outpost of the Glyderau mountain range sits proudly above the vast sprawling levels of the old Dinorwig slate quarry. Believe it or not but there is actually a hydro electric power station built inside Elidir Fawr – for good reason the associated visitor centre in Llanberis is called the Electric Mountain!
It can be approached from a number of vantage points but it is perhaps best to summit it via a circuit of Cwm Marchllyn. This route allows you take in the peaks of Carnedd y Filiast and Mynydd Perfedd – it also has the advantage of starting at a relatively high level.
Those of a more masochistic bent can opt for the somewhat relentless grind up from Nant Peris, and then, if they are feeling energetic continue round to bag an ascent of Y Garn before descending back to Nant Peris.
This is mountain terrain so always Prepare Well and Know Your Limits. During the winter season, typically from late October to April, there is a high probability that snow and ice will be encountered under foot. In these conditions ice axe and crampons are essential. Click the Safety & Access button below for more info.
Park up at the start of the reservoir road, which can be reached by following the Mynydd Llandegai road up from the western edge of Deiniolen. Ignore the left hand turn to Mynydd Llandegai; instead follow the road round to the right then up left to a gate, which marks the start of the Cwm Marchllyn reservoir road.
Street View Link to Car park
Safety & Access
Enjoy the Mountains Safely. Here are a few words of advice from Snowdonia’s Mountain Safe Partnership.
1. Prepare Well
have the right equipment with you for the best and worst-case scenario! You’ll need a map and compass, torch, food and drink, whistle, first aid kit and a fully charged mobile phone.
2. Have the latest weather and ground information.
Check the Met Office Mountain Weather forecast for Snowdonia before you set out and be prepared to turn back if the weather worsens – the mountains will still be here for you to enjoy the next time you visit.
3. Dress appropriately
the weather and temperature can change dramatically between the foot of the mountain and the summit. You’ll need strong walking boots, several layers of clothing including warm ones, gloves, a hat and waterproof jacket and trousers.
4. Know where you're going
Plan your route before setting off and ask for local advice. Have a map and compass and know how to use them and choose a route which is suitable for you and your group’s experience and fitness level. Find out how long it should take and when it gets dark.
5. Know your limits
whilst being very enjoyable, getting out into the mountains can be hard work – challenge yourself but be aware of the fitness levels, and experience of the group as a whole – not just your own.
The publisher of this website accepts no responsibility for the way in which readers use the information contained therein. The descriptions and recommendations are for guidance only and must be subject to discriminating judgement by the reader. Advice and training should be sought before utilising any equipment or techniques mentioned within the text or shown in any of the photographic images.
Hill walking and mountaineering are activities with a danger of personal injury or death. Participants in these activities should be aware of and accept these risks and be responsible for their own actions and involvement.