Tan y Grisiau

Rock Climbing

Clogwyn yr Oen | ©Si Panton

Tan y Grisiau

Rock Climbing

A collection of neighbouring crags (Craig y Clipiau, Craig yr Wrysgan, Clogwyn y Bustach and Clogwyn yr Oen) which sit above and near the Stwlan Dam access road. Perched high above Blaenau Ffestiniog the views across the surrounding landscape are extensive. The remnants of a bygone quarrying industry in Cwm Orthin add an extra surreal element to this dramatic location.

The rock is rough and pocketed and a real delight to climb on. The routes are fantastic, in fact as good as anything in Snowdonia. There is a good selection across the grade range from V Diff to HVS; there are also a few harder classics up to E5.


The crags get plenty of sunshine but the area does get quite high rainfall. Luckily the rock is mostly quick drying. Providing it is not raining (or snowing) climbing is possible throughout the year; that being said it can get pretty cold up here in the winter months.


From the small parking area for Cwm Orthin follow a path breaking off left from the Cwm Orthin track, cross the footbridge over the stream and continue over to join the private service road for Llyn Stwlan which runs across the hillside beneath Craig yr Wrysgan and Clogwyn yr Oen. Craig y Clipiau lies up to the right and is reached by turning right from the broken down buildings on the first level of the Cwm Orthin quarry workings.

Safety & Access
More info on Rock Climbing View on map

Safety & Access

The publisher of this website accepts no responsibility for the way in which readers use the information contained therein. The descriptions and recommendations are for guidance only and must be subject to discriminating judgement by the reader. Advice and training should be sought before utilising any equipment or techniques mentioned within the text or shown in any of the photographic images. Climbing is an activity with a danger of personal injury or death. Participants in this activity should be aware of and accept these risks and be responsible for their own actions and involvement.


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