Ffynnon Derfel (Derfel's well) is located some 350m north-west of St Derfel's Church (NPRN 43870). In the late sixteenth or early seventeenth century stone slate and rude masonry was noted to protect a spring, which formed a small reservoir measuring 4ft wide.

Sources include:
Jones, F, 1992, The Holy Wells of Wales

N Vousden, RCAHMW, 5 July 2012