Llanfair-y-bryn is the name of a rural community and Church in Wales parish in Carmarthenshire, Wales. Covering an area of some 95 km², it lies along and to the northwest and southeast of the A483 Swansea to Chester road immediately north of the town of Llandovery.
Two particularities of Llanfair-ar-y-bryn (English meaning: "St Mary's on the hill") are that
- the community and parish contain no settlement of that name: in 1801 it comprised the hamlets of Rhandir Abbot, Rhandir Canol, Rhandir Isaf, and Rhandir Uchaf; today the principal settlements are Cynghordy and Rhandir-mwyn
- the parish church was, until 1883, located one mile outside the parish itself, in Llandingad (Llandovery); in 1883 a new church (also called St Mary's) was opened at a more central location in Cynghordy.
The area is served by trains operated between Swansea and Shrewsbury via Llandrindod Wells by Arriva Trains Wales, which manages Cynghordy railway station, a request stop on the Heart of Wales Line from Llanelli to Craven Arms.
The old parish church, Llanfair-ar-y-bryn
The original St Mary's church stands a mile outside the parish on the northeastern edge of Llandovery, on the site of the Roman auxiliary fort of Alabum. William Williams Pantycelyn (1717-1791), generally acknowledged as one of Wales's greatest hymn writers, is buried in the churchyard there, having been a resident of the parish for much of his life.