Cwmtwrch is a village in the Swansea Valley, Wales, some 15 miles north of Swansea. A notable feature of Cwmtwrch is the Ffynnon which is a natural spring The name Cwmtwrch (Welsh language: 'Valley of the Wild Boar') derives from the “Twrch Trwyth” a mythical wild boar of King Arthur’s legendsand the ancient Welsh folklore tales of the Mabinogion in early Welsh literature. The legend relates to one of Arthur’s tasks: to rid the westernBrecon Beacons of the pack of wild boars that were terrorizing the people. Arthur chased the boars from Dyfed eastward towards Powys. On the Black Mountain (range), he picked up a large stone (the carreg fryn fras) and cast it towards the wild animals, striking dead the leader of the pack on the edge of a valley near Craig-Y-Fran Gorge. The big boar's body rolled down the valley and into the river which is now the River Twrch. The big stone is still on the mountain. In this area also is the legend of the Lady of the Lake of Llyn y Fan Fac.