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Bwlch Mawr and Gyrn Ddu Circular Walk from Clynnog

By Dave Roberts   

on May 1, 2016    4.33/5 (3)

Posted as a walk in – Europe, Llyn Peninsula, Wales, Wales Coast Path

Bwlch Mawr and Gyrn Ddu Circular Walk from Clynnog

Further Details

Route Summary:

Walk to lowly hills with great views on the Llyn Peninsula

Route Start Location: Clynnog Fawr

14.93 km 648 m 4-5 hours

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

Activivity Type: Moderate Walk

Summits and Places on this Route


There’s a garage at Clynnog Fawr.


Navigation in poor visibility over Bwlch Mawr

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:

Regular buses from Caernarfon and Pwllheli

Traveline for UK Public Transport

Recommended Maps


Bwlch Mawr and Gyrn Ddu Circular Walk from Clynnog Ordnance Survey Map and GPX File Download

Download file for GPS

Bwlch Mawr and Gyrn Ddu Circular Walk from Clynnog

This Circular Walk on the Wales Coastal Path used to be the route of the Llyn Coastal Path and it’s still well worth doing, probably more so than the official route as the views you get of the peninsula are stunning. There’s a tricky section over faint moorland and paths can be less obvious under bracken,so you’ll probably need to undertake a bit of map work on this walk.

The Route 

1 Start from the former inn in Clynnog and just past the Post Office on your left there is a minor road. You follow this road for a short while (1/2 a kilometre) before the road turns sharply left. Literally on the bend, there is a waymarker for a Bridleway, to your right. This then climbs steadily uphill through some bracken before veering left. Posts with blue arrows mark the way.

Sad sign of the times – the former village pub…

2 The track continues past a bunkhouse at GR SH415 491 and on into the derelict farm of Pen-yr-allt-uchaf (SH415 489). You will recognise the farm as it has an old, rusty, waterwheel in disrepair at its side. This is a building that occupies an unenviable spot, I could think of many worse places to live. Dream on anyway, unless you have twice the average income you can’t afford a starter home here these days. let alone something you’s actually choose to live in. Still, the one thing us landless masses have benefited from recently is the Right to Roam, and shortly after this farm you come to a track that leads you between two walls and at then open hillside. This is Access Land, that is marked on all new OS maps.

3 The crags of Bwlch Mawr look remarkably close from this point. You have two choices here, one is to follow the wall and green track right to take you past the plantation and eventually to the col between Bwlch Mawr and Gyrn Ddu. The other, and superior route, is to go off track and uphill. You need to be veering slightly left, but ideally you don’t want to reach the wall that climbs to the summit, not yet anyway! In good visibility you can pick a route with ease, there is an obvious wide gap in the crags. If you veer too far left and hit the wall, then following this up will take you to the summit, but the wall goes a rather direct route! If you follow my route, then a better route appeared to be to its left, which you can see on the Explorer maps as an area free of loose rocks.


4 The top is a rocky plateau, which can be damp underfoot in wetter weather. Head for the wall that cuts across your path and you have to clamber carefully over it (there’s a stone stile), then keep on in the same direction, keeping a wall to your right. If you can’t find the crossing point, you can follow the wall south instead. The summit is a small, rocky pile, and affords excellent views over the plain of Arfon and Foryd Bay. You can make out the route you’ve taken so far, and even make out the wheat fields at Llanfaglan. One thing that struck me is how wooded the area appears, as if one large forest. You can sit here awhile and see how many summits you can recognise. The vista stretches from the Carneddau, Snowdon, Hebog, Moelwyn to the Rhinogydd and further south. On a clear day, not a hazy one like today, you can see Cardigan Bay and the Llyn Peninsula below you.

5 Once you’ve had your cuppa at the Trig point, cross the wall that you followed to the summit and head for the wall that is now directly ahead of you, the one we crossed earlier. Keep slightly right, and avoid the crag that blocks your more direct descent. You now keep this wall to your right for the next kilometre, the only complication being yet another wall to cross. If you really hate climbing them, then there is a gap in the wall a couple of hundred metres to your left. You finally arrive at a section of plateau that would be severely boggy in the right weather, but you stop short of this and follow the reasonably good path right, over a wooden stile (I’d begun to forget what they were!). This path is followed across the Col (where you’d rejoin the route if you chose to avoid the summit by the route outlined above), and passes between two walls as a track before appearing again on open hillside.


6 To your right is Gyrn Ddu (but not the actual summit, that is just beyond), and your best bet is to head directly for the top, following a faint and broken track. As the ground becomes rocky, keep an eye out for the gap in the wall to your left, which is one of the few places to get across. Some of these gaps are plugged with barbed wire, so make sure it is a gap before you walk through it! You arrive at the top and you can see the summit of Gyrn Ddu ahead, looking simply like a giant cairn. Cross the short patch of moorland and you then need to clamber up the rockpile. The line I found, was to veer left, just be very careful of your footing as the rocks are exceptionally loose (they are also very abrasive on the skin) . It is only a 30 metre climb, and the summit is a cairn, with little space around.

However, it was here I’d find the surprise of the day, there was a string of prayer flags (I’m glad I didn’t call them bunting) strung across from the cairn to a nearby outcrop, that flapped noisily in the wind. The views are the one reason to walk here, as it offers these across to Yr Eifl, down to Trefor and down the peninsula. This made up for the gale force wind up here, it was enough to make me lose my balance, and on already loose rock, that’s not good.


7 You must now retrace your steps to the gap in the wall and descend to the track below. Follow this track right and it passes through meadows, past some derelict farmsteads to bring you out on the zig-zag path above Trefor.

8 Follow this track, taking care to find the final left hand zag towards the main road. Turn right at the main road along the A499 cycletrach and Wales Coastal Path which you can easily follow back to Clynnog Fawr.

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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