LLANVAIR-AR-Y-BRVN (LLAN-FAIRAR-Y-BRVN), a parish, in the union of LLANDOVERY, higher division of the hundred of PERVETH, county of CARMARTHEN, SOUTH WALES, a mile (N. E.) from Llandovery, on the turnpike-road to Builth; comprising the townships of Rhandir Abbot, Rhandir Canol, Rhandir Isav, and Rhandir Uchav; and containing 1649 inhabitants. The name of this pariah, signifying " the church of St. Mary on the hill," is derived from the situation of its church on an eminence within the lines of a Roman station in the adjoining parish of Llandingat, and which has been already described in the article on that place. In the township of Rhandir Abbot are some extensive lead-mines, the property of Earl Cawdor, situated near Pwll Pradog, a spot remarkable for the romantic scenery by which it is surrounded. These mines, which are among the principal in South Wales, have at different times employed from one to two hundred workmen; but the number is now materially diminished, owing to the long and laborious land-carriage to the port of Llanelly, where it was smelted in works erected early in the present century, expressly for that purpose. The surface of the parish is boldly undulated, and in some parts even mountainous. The living is a vicarage, annexed to that of Liendingat, and endowed with £1000 parliamentary grant: the tithes have been commuted for a rent-charge of £600, of which £444. 16. are payable to the Precentor and Chapter of St. David's, £111. 4. to the vicar, and £44 to an impropriator. The church, dedicated to St. Mary, and situated in Llandingat, nearly a mile from its own parish, is an ancient edifice, consisting of one large aisle, with a tower; but it presents no interesting architectural details. In the township of Rhandir Abbot is a neat chapel, called Nant-y-Bai, the living of which is a perpetual curacy, endowed with £200 private benefaction, and £1000 royal bounty; net income, £59; patron, Earl Cawdor: the original chapel was at Ystrad-Fin. There are three places of worship for Independents, and one for Calvinistic Methodists. About 25 children are educated in a day school, which is partly supported by Earl Cawdor, who allows the master £5 per annum, and partly by the parents; another day school, appertaining to Independents, contains 20 children, who are taught at the expense of their parents; and there are four Sunday schools, in which 220 males and females receive gratuitous instruction. The Roman road named the Sam Helen may be distinctly traced in several parts of its course through this parish to the station Loventium, at Llanio, in the county of Cardigan.