DERWEN, or DERWEN-YNIAL, a parish, in the hundred of RUTHIN, county of DENBIGH, NORTH WALES, 7 miles (S. w. by S.)' from Ruthin, containing 522 inhabitants. The village is situated near the source of the river Clwyd, and abounds with springs of excellent water, one of which, called Fynnon Sarah, was in great repute for its efficacy in the cure of cancer. About a mile from the village is a quarry of stone, which is soft and of peculiarly fine grain, and is much esteemed for sharpening the finest instruments, being found no where else in this country: great quantities are sent to London, and some of it has been exported to America. A fair is held on February I 1th. The living is a rectory, in the diocese of Bangor, rated in: the king's books at £10. 15., and in the peculiar jurisdiction and patronage of the Bishop of Bangor. The church, dedicated to St. Mary, is a small but interesting edifice, in the decorated style of English architecture, containing much beautiful screen-work, and ornamented with an elegant east window. In the churchyard there is a richly sculptured stone cross, in the same style of architecture, seventeen feet high, ornamented in alto relievo with a device of the Crucifixion, and with emblematic figures of Justice, Mercy, and Faith, in richly canopied niches. There is a place of worship for Calvinistic Methodists. On the river Clwyd is a mill for spinning woollen yarn, which was purchased with the amount of several charitable bequests, and produces at present a rental of A7 per annum; and in 1828, Godfrey Roberts, of Richmond, gave a rent-charge of £7, on an estate called TS, Cerrig, for the benefit of the poor: both these sums are distributed annually at Christmas. The average annual expenditure for the support of the poor is £238. 4.