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Cefn Du Trail Run

By Dave Roberts   

on March 14, 2012    No ratings yet.

Cefn Du Trail Run

Further Details

Route Summary:

Route Start Location:

5.1 km 121 m

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

Activivity Type: Easy Walk, Trail or Fell Runs

Summits and Places on this Route


Check out the businesses nearby for more places to stay and drink.


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 :

Public Transport:

Traveline for UK Public Transport

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Weather Forecast:

Met Office Snowdonia Mountain Weather

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Cefn Du Trail Run Ordnance Survey Map and GPX File Download

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Cefn Du Trail Run

If you’re just getting into trail and fell running, you may want to get off path without all that ascent. This easy route starts at over 350m at the Bwlch y Groes car park before a steady ascent takes you through the quarries to the summit of Cefn Du at 441m. The return path is easily lost – we ended up going cross country for a bit before an easy return on tarmac. You can then add a short loop to the bwlch to make the distance up to 5km.

The Route

Setting off from the car park, continue uphill on the track you came up on. This is a slaty path that soon veers off left and climbs slowly but steadily.

The track takes you to a wall where you need to turn left and you can choose to to turn a very sharp left or follow the wall which is a little easier to navigate. The terrain soon changes from nice, short grass to ankle breaking heather that will be with you until you arrive back on the tarmac track.


Follow the fence, which will turn left at 90 and then turns right at 90 but has clear path all the way. You should see the ‘summit’ ahead to the left.

There’s a trig and an old brick ruin that was part of Marconi’s wireless station, with sections even as far as half way up Moel Eilio. The Beacon Centre used to be the main building. If you’re lucky, there’s a decent view from here towards the higher mountains, but the moorland limits the view below this.


You’ll have no time to hang about as you continue to follow the fence downhill, until it turns a sharp right. You can continue with the fence and pick a way lower down towards the road like we did, but the best way is to continue directly south from the fence and join the main path as shown  on the map. This section is tough to run as the path is rocky and impossible to see in the deep heather, so you have to proceed with care as you don’t know whether your feet will be landing on soft mud or hard rock.


Once on the track, follow it left for about 1km to the car park. You can extend the run by running to the far end of the car park which narrows to a path that eventually takes you to the track you started on. Cross to the gate at the bwlch and easily follow the rough track back.

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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