Walk up Elidir Fawr From Marchlyn Mawr and Deiniolen
The Marchlyn Circuit is a classic walk, popular with locals as it can be done conveniently from nearby towns in a half day or evening.
Route Start Location: Deiniolen
|10.16 km||630 m||4 hours|
Calculate the time using Naismith’s Rule and factor in your own pace.
Activivity Type: Hard Walk
Summits and Places on this Route
Route-finding in mist, esp over Elidir Summit and descending from Carnedd y Filiast
Free roadside parking.
Frequent-ish bus service to Deiniolen from Caernarfon or Bangor.
Walk up Elidir Fawr From Marchlyn Mawr and Deiniolen Ordnance Survey Map and GPX File Download
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Walk up Elidir Fawr From Marchlyn Mawr and Deiniolen
The walk up Elidir Fawr from Marchlyn Mawr near Deinolen and Dinorwic, is a hidden gem. While it has a bit of a slog on the initial ascent, it is certainly not in the same league as that up from Nant Peris! The far north peak of Carnedd y Filiast has the encroaching Penrhyn Quarries nearby, and the main summit of Elidir Fawr has a hydro power plant built inside it, hence the nickname of ‘Electric Mountain’. This route makes a great start for a full traverse of the Glyderau, or for a quick half day’s walk. Quicker walkers can also walk out to Y Garn and still keep the walk at around four hours.
Walk up Elidir Fawr From Marchlyn Mawr and Deiniolen Route Description
The ascent is the same as the one done last year over to the Glyderau, but descending via Carnedd y Filiast. You can easily reverse the route. This time, I knew of the pitfalls of the walk and this was essential as we had four hours in which to complete it before it got dark.
The walk starts at the crossroads above Deiniolen (SH593 631), the road is signed for Marchlyn before you turn into Deiniolen from the main road. The road is followed up and used to take you all the way to Llyn Marchlyn Mawr. You can take the track right and ascend the slopes of Elidir Fach from there, but we took the steep, direct route by the smaller lake, Marchlyn Bach. Crossing the road, you come to a locked gate. You climb over this and follow the wall to your right. A very faint path does start here, but fades out towards the skyline. In mist, just beware of the crags to the left.
Once the skyline is reached by a very steep pull, the walk eases. Elidir Fach is easily attained and from here you can walk a little further towards Llanberis to get a superb view of Llyn Padarn. In fact, it’s quite a god viewpoint all round. Behind you is a strange flat area, before the steep scree of Elidir Fawr is to be tackled. It is steep, but you’re quickly at the top of this (took us 10mins). There’s a small cairn at the top of the path, which is essential in finding the path if you are descending.
The ridge of Elidir Fawr will slow you down more than the scree. Rocks are often loose, and if it’s wet they can be treacherous. This is another great viewpoint, but today the cloud had closed in just as we reached the summit. All we got were tantalising glimpses of the view, which pleased nevertheless. It is here we spotted the only other people out on the hill this evening, a couple of guys who we’d spotted walking on the high path above Cwm Dudodyn from Y Garn.
The descent to Bwlch y Brecan is steep in places and the path often loose so care is needed. If you keep as close to the ridgeline as possible then you’ll be rewarded with views of Marchlyn Mawr to your left and the imposing bulk of Elidir Fawr behind you. Just keep an eye for the path back up to Mynydd Perfedd. It is quite faint, and if you miss it then a good overshoot feature is a nasty gully to the left that looks like a steep and eroded footpath.
The fence on Mynyd Perfedd is a good feature to handrail in mist as it leads you directly to the summit shelter, but from here you’ll need to take a bearing in mist as the path is faint and the next kilometre or so a wide, flat ridge. Just make sure that you don’t veer to the right as the sheer cliffs on Carnedd y Filiast are led to by convex slopes that you could entice the weary over. However, if you spot the cliffs then they lead you towards a stone wall and a stile. Cross the stile and make your way to the summit, but again the path is faint or nonexistent, so good compass work is essential.
The summit is a jumble of shelters, which weren’t needed on a fine evening like this, though it was cool in the wind (August feeling more like April). Descent is difficult to find, but follow a faint path NNW where it crosses rocks and down to grass before veering left between higher ground (there’s a ring contour on the OS map). Beyond this it’s reasonably clear where the path starts its steep descent but soon takes a sharp right that is easily missed but is then clear all the way down. If you miss this then you’ll be clambering over boulders all the way down. The path does vanish near the col, but you’re nearly there by then and doesn’t cause any difficulty. There’s a small pool in the col (looks like a stylised fish) from where the main path turns left to descend. It is worth carrying on to the 720m summit at the end of the ridge for the views down into the Penrhyn slate quarries.
Return to the pool and take the narrow path down. Carnedd y Filiast looked imposing tonight, possibly due to the evening light. Certainly it looked more than the hundred metres or so that it rose from the col. The descent is a clear path, and is easy to follow down to the dam road below.