DYFRYN-GWY, a township, in the parish of CWM-TOYDDWR, partly within the new limits of the borough of RHAIADR, and partly in the hundred of RHAIADR, county of RADNOR, SOUTH WALES, 2 miles (N. W.) from Rhaiadr, containing 507 inhabitants. The road from Rhaiadr to Aberystwith passes through this township, running, in the upper part of its course, along the left bank of the river Elain, which has its rise here in Llkn Gwingy, on the border of Cardiganshire; and the river Wye flows on the north-eastern side of it: there are two manufactories for flannel. Within the limits of the township are several cairns, the most remarkable of which is Tommen sant Fraid, said to cover the remains of the patron saint of the parish church, which is situated in this township. On the banks of the Wye, nearly opposite to the site on which Rhaiadr castle stood, are traces of an encampment: though a part of the intrenchments were demolished last year, an artificial mount still remains, probably the site of the keep of an ancient castle, which it is said communicated with the former one by a passage beneath the river Wye.