Bryn-y-Castell is marked as Settlement on the Ordnance Survey map, around SH 728 849. To the right is Llyn y Morwynion (see under 'Legend of Lleu Llaw Gyffes and Blodeuedd') and along the road to the east is Pont yr Afon Gam, worth visiting for its excellent café.
The hill-fort of Bryn-y-Castell appears on first inspection to be a small but remarkably well-preserved fort. In fact, it was comprehensively excavated in 1979-85 and the rampart and internal buildings were partly reconstructed afterwards. The site was used mainly for iron-working before the Roman invasion of the area. After the local garrison left, in the 2nd century AD, the industry was re-established outside the defences of the fort, around the hut below it to the north-west. The iron came from bog ores in the nearby peat bog, and much of the local forest was felled to provide charcoal.
The landscape of this area is full of Welsh legend. Tomen-y-Mur (see separate link) was the home of the magical prince Lleu Llaw Gyffes and his wife Blodeuedd. She betrayed him, and he eventually took revenge on her and on her lover Gronw. Blodeuedd and her maidservants ran away along the line of the Roman road and across the Cynfal to a court in the mountains, but they were afraid to turn their backs on Gwydion and, unable to see where they were going, the maidens fell into Llyn y Morwynion, the Lake of the Maidens, and were drowned. Was Bryn y Castell the ‘court’ they were making for and, if so, does this suggest a tradition that it was occupied in the early medieval period? Or did the story develop around a known ancient feature in the landscape?