Llyn Cerrig y Myllt and Nantmor Trail Run  No ratings yet.

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Route Summary:

13.76 km 552 m

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

Start and Finish:

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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.

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Llyn Cerrig y Myllt and Nantmor Trail Run Route Map and GPX Download

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Summits and Places on this Route

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Llyn Cerrig y Myllt and Nantmor Trail Run Details

This is a reasonably rough trail run that can be started from Gelli Iago or Nantmor  in Snowdonia. It’s equally at home as a mid-level walk, and the excursion to the lakes is optional and the trail run works better without this dog-leg.

1 – Start off from Gelli Iago (see map) and walk towards the farmhouse, following the directions to walk around the rear of the building, across a footbridge and to the initially very steep section.


2 – This is the steepest section of the route, though it relents after half a kilometre or so as you enter the valley above. The path is generally rough going, but easy to follow. Cnicht dominates the view, although as you’re looking sidelong at the ridge it doesn’t seem as impressive.


3 – After a further 1.5km, you reach Bwlch y Battel which is easily identified by the stone wall you have to cross. You can follow this wall (after crossing) in order to get up to Llynnau Cerrig-y-myllt or continue along the path.


4 – Llynnau Cerrig-y-myllt are reached by a bit of navigation, though nothing beyond a bit of easy map reading and simple bearing if needed. In reality, you just tend to head for the high ground, hoping for the best. The route on the map above takes you to the southern lake, but you can find numerous trails in order to find your way around it to the northern one. Just be aware that in mist, this can be a tricky place to find your way around, and makes for some valuable navigation practice. The space in between is a superb wild camping spot.


5 – Descend by the same route to the bwlch.

6 – The next 2km or so are along a path, but it’s often boggy and rough and makes the going tough. You skirt around a boggy lake, before descending along the stream and the eventual joining of the Cnicht path and some easier going. Follow the Cnicht path as far as the Croesor – Nanmor track at SH628 450 and turn right.


7 – This track takes you steadily down towards Nanmor and the minor road at Bwlchgwernog. It can be a bit boggy in places, but nothing unexpected on a good run/walk in these parts. From Bwlchgwernog, you could follow the minor road right to return to the start (3.5km or so) or continue across towards Nantmor village along the minor road from where you can soon return to some more trail.


8 – Turn right past the chapel, and the route continues along farmland and the next section can be rather tricky to follow without due care and attention to a map. Although most of the rights of way to still lead in the right direction, whicch is at least a bit of a comfort. The middle section is along a good farm track, but you’re soon off that again towards the farmstead at SH621463 where the going is rather muddy before finally becomes more straightforward.


9 – Pass behind the farmstead, and you’ll descend into some ancient woodland. This path is easy enough to follow now along 2.5km of the valley, with the main obstacles if you’re running being other path users as it’s narrow in places. It’s also reasonably flat, so it makes a decent end to the run, but along proper trail all the way.


10 – This is over too soon, and you’ll reach the minor road just south of your starting point, where turning left will find you back at the start in a few minutes.

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Dave Roberts

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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