Ffynnon Gyffyr is located on the West bank of the Afon Cwm Bach, close to but lower than the track leading to Cwm Maelog farm. It is thought to have been connected with the nearby Hen Eglwys, possibly being used as a baptistry, although later it became associated with Margam Abbey and was adapted to a cold bath house.

The building is rectangular with a vaulted roof, an arched doorway in the south wall and a small lancet window on the east side. The interior contains an L-shaped pool, about 1m deep with well built stone walls. Although the pool is fed by a water inlet at the Northern end, it is evident that water enters the pool at a lower level through the stonework. The building was once covered with flagstones and tiles, some of which are still in situ and about half of the interior is still covered with limewash, including the vaulted ceiling.
Source: Cadw scheduling description. FF/RCAHMW 05.06.2008