Braich Rhydd Slate Quarry was located north-east of the village of Y Fron, on the lower southern slopes of Moel Tryfan. It was a pit working with material originally sent out through Cilgwyn (Nantlle). Later it was sent out on the North Wales Narrow Gauge Railway via Braich Quarry (NPRN 400648). Steam was used latterly for pumping and hauling, and wind power was tried for pumping in 1827.
The quarry is variously depicted on Ordnance Survey County series maps (Caernarvon. XXI.5 edns. of 1889, 1900, 1915). The quarry was amalgamated with Fron Quarry (400650) in 1882; working ceased in about 1950.
Surviving remains, in 1991, included the pit, a few ruinous buildings (including part of the mill, re-used), and vestiges of an incline and internal tramroad formations.

Sources:
Lindsay 1974 (Hist. N Wales Slate Ind (1974), p.319.
A.J.Richards, A Gazeteer of the Welsh Slate Industry (1991), 86.
RCAHMW Air Photo: 945129/48-9.

David Leighton & John Wiles, RCAHMW, 14 January 2015