GLYN, a chapelry, in the parish and hundred of Devynock, union of BRECKNOCK and county of Brecknock, South Wales, 4 miles (W. by S.) from Brecknock; containing 245 inhabitants. It is situated on the western declivity of elevated ground, to the south of Pen-Pont Park, near the source of the Camlas brook, and on the left bank of the river Tarrell. The area is 2260 acres, of which 50 are common or waste land. The living is a perpetual curacy, endowed with £800 royal bounty; net income, £80; patron, the Vicar of Devynock, who receives a third of the amount for which the tithes here have been commuted, namely £133. 10. 6., the other two-thirds being divided between the Bishop of Gloucester and Bristol and the impropriator, who receive £44. 10. 2. each. The chapel is dedicated to St. Illtyd, and sometimes gives the name of Llan-Illtyd to this division of the parish. On an adjoining eminence, near a pool, are two large stones, placed six feet asunder, at each end of a small tumulus, which is called Bedd Gwyl Illtyd, or "the grave of St. Illtyd's eve," from the ancient custom of watching there on the eve of the festival of that saint, who was supposed to have been buried here.