The Best Pen yr Ole Wen Walking Route

Pen yr Ole Wen is a mountain in Wales found in Snowdonia National Park. The Welsh name Pen yr Ole Wen translates to Head of the White Slope. At 978m high it is the 7th highest peak in Wales and offers several walking routes to it’s summit. 

Hikers can reach the top of Pen yr Ole Wen directly from Ogwen Cottage via a loose scree walk, from the North via Braich Ty Du or from the east via a short scramble.

In this guide I describe what you can expect on a Pen yr Ole Wen walking route that ascends from the east, and incorporates the high Carneddau of Dafydd and Llywelyn (Llewelyn in English).

Pen yr Ole Wen

Snowdonia has a plethora of hiking routes to choose from. Click here to learn about 10 of the best Snowdonia hiking routes!

Walking The Carneddau

The Cardneddau (not the Carneds!) are a range of mountains in Snowdonia consisting of 32 peaks, 7 of which are the highest mountains in Wales and England. The highest in the range is Carnedd Llywelyn which stands at 1064m, closely followed by Carnedd Dafydd at 1044m and Pen yr Ole Wen at 978m.

The Carneddau are found in the northerly end of Snowdonia and are high mountains known for their large open vistas. A walk in the Carneddau offers a superb big mountain day in Wales largest National Park.

In Winter snow tends to accumulate on the Carneddau plateaus and perhaps sheds some light on the name given to Pen yr Ole Wen (Head of the White Slope), which sits at the southerly end of the range.

Frustratingly, the Carneddau are not shown in their entirety on one side of an OS Explorer Map – they are split over two sides. So you can either take the OS Explorer OL17 and turn the map over once you get to Carnedd Llywelyn, (difficult on a windy day!) or sacrifice some details and use the Landranger 15 map.

During my explorations of the high Carneddau I have generally been blessed with gloriously clear skies. Since the Carneddau are so open, with clear skies it’s often possible to see your route ahead of you, but in poor visibility map and compass work are required. 

Hiking Pen yr Ole Wen and the High Carneddau

  • Distance: 15km
  • Elevation gain: 980m 
  • Time: 7 hours
  • Start and finish location: Glan Denau on the A5
  • Summits: Pen yr Ole Wen, Carnedd Dafydd, Carnedd Llywelyn

Trail Description

This epic mountain day begins from the beautiful Ogwen valley. Park in the lay-by on the A5 near Glan Denau and head towards the entrance. Walk along the gravel road and past the buildings to begin on the path proper.

There are wooden posts with way markers to lead the way initially, though these soon dwindle out.

The climb up Pen yr Ole Wen begins gradually and soon you will have to cross Afon Lloer. After crossing the river, the path becomes a little patchy and can easily be lost. To stay on track keep following the river upstream, with the river on your right hand side.

After crossing a stone wall the path again becomes clear as it branches away from the river and leads in a westerly direction. The trail then becomes a little rockier and crosses a small plateau before you are faced with the first scramble of the day.

This short Pen yr Ole Wen scramble climbs along a crack in the rock and finding a suitable route is quite straight-forward. Beyond this there is a long but steady climb to attain the the summit of Pen yr Ole Wen.

Be sure to appreciate the views down into Cwm Lloer to your right as you climb.

You’ll be relieved to reach the top of this first peak, knowing that the majority of the climbing for the day has been now been completed.

The summit of Pen yr Ole Wen is a fairly flat affair but does allow for 360 degree views. Take a moment to appreciate views of Tryfan and the Glyderau and if the weather is good, Snowdon beyond that.

For a list of hikes that explore the Glyderau range, take a look at this guide.

Views from the summit of Pen yr Ole Wen

Moving off from Pen yr Ole Wen to the north, there is a small descent  before a short climb towards the summit of Carnedd Dafydd. The path is rocky and a little unclear at times but continues in a north easterly direction until the summit is reached.

There are multiple shelters here to take a short rest but I suggest continuing onto Carnedd Llywelyn before tucking into your lunch!

Views of Carnedd Dafydd on this Penyr Ole wen walking route
Carnedd Dafydd and Cwm Lloer

The path from Dafydd to Llywelyn is a glorious ridge walk offering fine views for the whole journey. (Weather permitting of course!). The path is clear from the summit, then becomes a little vague before turning into more of a defined ridge.

This defined ridge section comes just before the main ascent of Carnedd Llywelyn, at Bwlch Cyfryw-drum. Along this ridge you can appreciate the classic U-shaped glacial valley to your left and Cwm Llugwy with it’s reservoir to your right.

Looking across to Cwm Llugwy you should be able to pick out your descent path along the side of Ffynnon Llugwy reservoir.

Carnedd Llywelyn on a walk from Pen yr Ole Wen
Looking along the ridge to Carnedd Llywelyn

It’s a short climb from the ridge to the final and highest summit of the day. At the summit of Carnedd Llywelyn there is a stone shelter perfect for taking a break and escaping the wind.

Llywelyn is another non-distinct plateau summit but does offer fine views in every direction on a clear day.

A view across the Carneds
The view from Carnedd Llywelyn, looking across to Carnedd Dafydd and beyond to the Glyderau

As a big flat summit, navigating your way off the top of Llywelyn can be tricky, especially in poor visibility. Thankfully, the path you require is conveniently located next to the stone shelter and heads off in an easterly direction.

Did you know? Dafydd and Llywelyn are the names of two Welsh Princes.

Fabulous views on a Pen yr Ole Wen hike
Cwm Llugwy

The path is quite distinct and quickly becomes steep, with loose scree in places. It then levels off, before crossing a craggy pinnacle (the first pinnacle can be easily skirted around). The descent from this craggy pinnacle towards Bwlch Eryl Farchog provides the next scrambling adventure of the day!

Taking care to pick your way between the boulders, you are then presented with a large slab of rock which might seem intimidating at first! Choose your decent down this rock face carefully, using cracks in the rock to your advantage.

From the Bwlch, the path then descends steeply into Llugwy valley and again has some loose scree in parts. Once the descent is done there is an enjoyable stroll alongside the reservoir before you are abruptly deposited onto a tarmac road. Yuck!

What follows is a rather tedious 2km trudge along this reservoir road down to the A5 below.

Cross the A5 and follow it back towards Llyn Ogwen for around 300m. Take the turning into Gwern Got Isaf campsite on the left and walk along the driveway until you reach the bridleway on your right hand side.

This bridleway provides a direct route back towards the lay-by where your car is parked, via Gwern Got Uchaf campsite.

Either one of these campsites would provide the perfect location for your overnight stay when undertaking this glorious Pen yr Ole Wen hike. Alternatively there is the YHA Hostel just opposite Ogwen Cottage.

What to pack for your Pen yr Ole Wen Walk

Make sure you have everything you need for a day in the mountains with this day hiking packing list.

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A hiking guide describing what you can expect when walking Pen yr Ole wen and the high Carneddau including distances and times

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