A Guide to the Moelwyn Mawr Walk via the Snowdonia Slate Trail
A Guide to the Moelwyn Mawr Walk via the Snowdonia Slate Trail

A Guide to the Moelwyn Mawr Walk via the Snowdonia Slate Trail

There are several ways that you can climb Moelwyn Mawr in Snowdonia. I hiked the mountain with a friend on a hot summer’s day and we did an 8.6 km circular Moelwyn Mawr walk starting from the village of Croesor that followed the Snowdonia Slate Trail.

The hike is a steep, tiring climb that requires a decent level of fitness. But the hard work is worth it. From the top you get incredible views of Cnicht and in the opposite direction you can see all the way to the coast and its beaches.

Table of contents

A foxglove plant in the foreground and Cnicht mountain in the background.

Moelwyn Mawr

Moelwyn Mawr is one of the peaks in the Moelwynion, a group of mountains located in central Snowdonia, North Wales. The mountain stands at 770 m tall and from the summit you have commanding views over the beautiful Vale of Ffestiniog.

Moelwyn Mawr has a couple of interesting features that make the hike more than just a scenic walk.

Firstly, there’s the Stwlan Dam tucked into the East side of the mountain that boasts some interesting architecture. The dam is part of the Ffestiniog Power Station and holds back the Llyn Stwlan reservoir.

Secondly, Moelwyn Mawr has a rich slate mining history and the remnants of the once booming industry are there to see. This includes derelict slate houses, enormous piles of slate and abandoned tunnels that journey deep into the mountain.

Moelwyn Mawr walk route

  • Distance: 8.6 km
  • Duration: 3-5 h
  • Difficulty: hard

The Moelwyn Mawr walk route detailed in this guide is a loop that starts from and finishes at the small village of Croesor. The initial sections take you along paved road and the Snowdonia Slate Trail, which are easy underfoot and not very steep.

But once you come to the first building ruins from the slate works, things get tough. You leave the slate trail behind to clamber up the mountain side as you push for the summit. This final part of the ascent makes this Moelwyn Mawr walk a difficult one.

Now let’s get into the route in full.

You start out from the free car park in the village of Croesor. Leave the car park by the narrow lane at the opposite end to the main entrance. This lane takes you past Oriel Caffi Croesor and onto a road. Head left and continue down the road away from the cafe.

If you look up to your left, you’ll see Cnicht, a triangular alpine-esque mountain. Moelwyn Mawr is on your right, but you won’t be able to see it just yet. Continue down the road and after a couple of hundred metres you’ll come to a point where the road splits into three lanes and there some houses.

Kester at a point of the Moelwyn Mawr walk where the rod splits into three lanes.

Continue straight towards the impressive valley that now opens up in front of you. Here the road forks and you have the option of keeping straight or bearing right.

Continuing straight will take you all the way along the road that sticks to the bottom of the valley to the valley’s end. Bearing right allows you to join the Snowdonia Slate Trail and climb up the side of the valley. You’ll want to bear right and begin the ascent of this Moelwyn Mawr walk.

Now you’re on the Snowdonia Slate Trail and the paved road turns to a bumpy unkept dirt road used by farmers. Although the underfoot is now a bit trickier, it’s nothing too challenging. Although things do become steeper, as you are now heading up towards the old Croesor Quarry. However, this section of the trail really allows you to take in what I thought were stunning surroundings.

A house at the foot of Cnicht mountain as seen from the Moelwyn Mawr walk.

As you climb higher, you get a sense of the scale of the landscape. And even though Moelwyn Mawr is the tallest point in the area at just 770 m, the towering sides of the valley seem much taller.

Keep following the slate trail and after roughly 30 minutes you’ll come to a plateau and the beginnings of what’s left of the old Croesor Quarry. Now you have another choice to make. You can explore the quarry before starting the difficult section of the hike. Or you can summit Moelwyn Mawr first and explore the quarry on the way back down to Croesor.

Croesor Quarry

We chose to explore the quarry on the way down. But whichever you choose, to summit Moelwyn Mawr, you’ll need to leave the quarry behind pretty much at the point where you first arrive to it from the valley floor. At the building in the picture below, you’ll want to head right, away from the quarry and up the side of Moelwyn Mawr.

Ruined buildings at Croesor Quarry on the Moelwyn Mawr walk.

Now it’s time to dig in and enjoy the challenge of the difficult section of the trail. Up until now, the trail has been a walk, but here it becomes a proper hike and you’ll need to get your legs pumping. 

There is a faint grassy trail that you can follow here. However, it isn’t easy to see at first. But this isn’t a problem as the summit is clearly visible. So as long as you’re heading uphill and in the direction of the summit, then you’ll be going in the right direction. We didn’t stick to the faint grassy trail, instead we blazed our own path.

Whichever way you choose to ascend from the quarry, you’ll come to a ridgeline where you’ll see a clear dirt trail. On a good day, you can see the trail leading all the way up the summit of Moelwyn Mawr.

Kester looking at Moelwyn Mawr.

Join this trail and follow it up all the way up to the summit. At first the ridge is flat and gives you a chance to catch your breath after the steep ascent from the quarry. But it doesn’t take long for this final section of the hike to become challenging. As you begin the final ascent, the trail once again gets steep and demands good fitness.

As you come to the top, you’ll see a trig point (a small stone pyramid-like pillar) marking the summit. Now it’s time to take a moment and enjoy the views from the highest point of this Moelwyn Mawr walk.

The trig point atop Moelwyn Mawr.

Parking for this Moelwyn Mawr walk

There is free parking in a small car park in the village of Croesor. Keep in mind that although Moelwyn Mawr and Cnicht are not the most popular mountains with hikers in Snowdonia, the fact that the car park is small and free means that during busy periods, it can fill up quickly. This means it’s important to get to the car park early, or hike Moelwyn Mawr during a quieter period.

More Snowdonia travel content on A World Over

I’ve got more detailed travel advice and recommendations for Wales on the A World Over blog including more guides to adventures in Snowdonia.

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