Pen Y Gader or Gadair Fawr (head of the big chair) standing at 800m with a prominence of 47 m. This hill suffers from the most commonly mistaken identity in the Black Mountains as it distinctive peaked shape and hight means it is easily confused with its sister peak Waun Fach . However Gader Fawr does not suffer from the unsightly and sometimes impossible conditions on Waun Fach as the summit of Gader Fawr sits on a well drained bronze aged cairn and is always a pleasure to spend time upon even if the journey can be a bit muddy. The views from Gader are by far the finest the Black Mountains has to offer. ( since the writing of this article the Brecon Beacons National Park have done extensive work to the path which joins Waun Fach and Gader Fawr more info can be found here )
The summit can be tackled form many different angles with several great walks to be found on the walking routes page with the Twin Peaks Blog. My personal favourite is up from Llanbedr and Crug Mawr as the gradual ripples in the foothills build up rhythmically to the crescendo that is Gader Fawr
With out a shadow of a doubt the finest views of Pen Y Gadair Fawr are from the south and west as from the north and east the slopes are infested with coniferous plantation and to tackle this hill via the direct route up from the Grwyne Fawr valley is the reserve of the insane and those who attempt the infamous Platinum challenge in the BBMC run by Longtown Mountain Rescue .
This shapely summit has attracted the attention of people for thousands of years as on its flanks was erected the highest standing stone in Wales, Maen Llwyd which stands at a height of 2 meters and at an altitude of 520 meters above sea level
Pen Y Gadair Fawr oozes beautiful spring water as well as funnelling mountain run off. Like its sister peak Waun Fach, Gadair feeds both the Grwyne Fechan and Grwyne Fawr rivers. The Nant Y Gadair which it shares with Waun Fach flows down the valley between them to join the Grwyne Fechan river. The Gargwy Fach rises almost on the summit of Gadair Fawr its waters are fortified by waters from lower Pen Twyn Mawr, then it is becomes known as Gargwy Fawr which carves its own valley around Twyn Du before also joining the Grwyne Fecah just above the famous Hermitage ruins. The Feeding of The Gwryne Fawr occurs post reservoir and provides a wonderful direct footpath up from Grwyne Fawr valley to the summit of Gadair fawr. The rivers walks can be found on the Walking Routes page
The Grwyne Fechan river walk and the valley is featured in this short video