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On the Edge of Yr Arenig – Mynydd Maentwrog and Graig Wen

By Dave Roberts   

on August 13, 2015    No ratings yet.

Posted as a walk in – Europe, Snowdonia National Park, The Arenig, Wales

On the Edge of Yr Arenig – Mynydd Maentwrog and Graig Wen

Further Details

Route Summary:

Wild route on the edges of the Arenig that feels remote.

Route Start Location: Tomen y Mur car park

12.19 km 397 m 4 hours

Calculate the time using Naismith’s Rule and factor in your own pace.

Activivity Type: Moderate Walk

Summits and Places on this Route


Some facilities in Trawsfynydd.


Rough and pathless – nav skills will be needed.

Remember that we cannot outline every single hazard on a walk – it’s up to you to be safe and competent. Read up on Mountain Safety , Navigation and what equipment you’ll need.

Parking :

Parking at start.

Public Transport:

The Trawscambria passes along the A470, but you’ll need to walk in to the start of the walk.

Traveline for UK Public Transport

Weather Forecast:

Check out our Best Mountain Weather Forecast?

Recommended Maps


On the Edge of Yr Arenig – Mynydd Maentwrog and Graig Wen Ordnance Survey Map and GPX File Download

Download file for GPS

On the Edge of Yr Arenig – Mynydd Maentwrog and Graig Wen

The Arenig hills, along with the Rhinogydd on the opposite side of the A470, usually make me think of walks that are as remote as you can get in Snowdonia. This usually comes with a price, as the going is arduous or boggy. So, with a walk up these pair of Deweys, we were expecting a hard slog and the distinct possibility of losing a boot or two in the bogs on the way.

We were, however, pleasantly surprised with how easy the going was over Mynydd Maentwrog and Graig Wen, which somewhat resembled the tops of the Moelwynion around Ysgafell Wen. While these hills may not be for everyone, a bit of route finding is necessary, they’re recommended for those looking for a quiet viewpoint without actually going that far.

1 This route starts off from the Tomen y Mur car park between Ffestiniog and Trawsfynydd (use the route finder to the right to get here – it’s almost impossible to spot until you pass it). You can get a bus service to the main road, from which you can walk the extra 1.5km or so to Tomen y Mur. Continue along the road past the car park and take the dirt track directly ahead.

Mynydd_Maentwrog (1 of 35)

2 This is a good track and you soon pass a small lake – Llyn yr Oerfel – with a smallholding next to it. Keep an eye out for the path that veers off to your left soon after the junction for the small holding. This is easily missed, but is a surprisingly clear green track once you’re on it.

Mynydd_Maentwrog (9 of 35)

3 This track continues steadily uphill, and we followed it until it reaches a plateau at around the 430m contour and the ground becomes a bit boggier. So rather than follow the path on the map, we headed along the edge of the plateau along some crags and then directly uphill.

Mynydd_Maentwrog (7 of 35)

4 The slope soon levels out, and a faint path takes you along the complex terrain across to Foel Fawr, the summit of Mynydd Maentwrog. It’s marked with a cairn and it’s an obvious summit, but this is the sort of terrain that requires careful navigation in mist. Ideal ML training terrain. It’s an excellent viewpoint, which makes the walk worth it. You’re surrounded by a Who’s Who of Snowdonia’s mountains, even if you’re sat on one’s that unknown to most.

Mynydd_Maentwrog (11 of 35)

5 The trip across to Graig Wen involves some wide detours to avoid large boggy areas. While they’re extensive, they largely keep to themselves and so don’t make the going too difficult. The initial heading was NE from the summit area, towards the forestry but not all the way to the edge unless you want to do some serious bog trotting! Before you reach the first pool, there’s a clear (ish) track cutting across and down towards the breached dam at SH732 393. This dam is basically the main waypoint between these two summits and it’s essential that you find it.

Mynydd_Maentwrog (15 of 35)

6 Once across the dam, the going becomes easier, passing high above Llyn y Graig-wen where a decent track can be followed to the northern flanks of Graig Wen where you should head south as soon as you can rather than continue around.

Mynydd_Maentwrog (17 of 35)

7 Graig Wen is again a decent viewpoint, but a much flatter and less distinct summit than Foel Fawr. We considered continuing along the ridge to Foel Cynfal, but we reached a hillock and decided it was best to strike downhill from there.

Mynydd_Maentwrog (23 of 35)

8 You’ll need to head for the Mine (disused) on the map, with the going easy enough along grassy slopes. As you reach the mine, keep clear from the fenced off area for obvious reasons, and cross slightly downstream. This section is a bit boggy, and the wettest section of the walk. It might be worth checking the stream, just in case, as this was the site of the Prince Edward Gold Mine.

Mynydd_Maentwrog (26 of 35)

9 There’s now a good track, and ugly pylons, that’s easy to follow. Turn right at the ruined farm of Dolddinas, and after 300m you take the track right rather than turning left.

Mynydd_Maentwrog (29 of 35)

10 This track finishes soon after, and becomes a pleasant green track. There’s a ford to cross at Dolbelydr, just take care not to follow the track to your left, and take the path uphill. There’s an eroded path as well that you pass first, avoid this one.

Mynydd_Maentwrog (32 of 35)

11 Within minutes, you’ll arrive at Braich Ddu Quarries which are very much not disused. It’s only a few 100m before you find yourself on familiar ground from earlier on, and the final leg of the walk.

Mynydd_Maentwrog (34 of 35)

Finally – take the opportunity to visit Tomen y Mur which has both Roman fortification and Norman motte remains.

Mynydd_Maentwrog (35 of 35)

Dave Roberts founded Walk Eryri in 2004, with the aim of providing routes that are off the beaten track. Walk Eryri is now part of Mud and Routes which continues to provide more off beat routes and walks in Snowdonia and beyond. Dave has been exploring the hills of Eryri for over thirty years, and is a qualified Mountain Leader. Dave also established Walk up Snowdon, Walk up Scafell Pike and Walk up Ben Nevis just to mention a few.

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