Ffynnon Fair is a sunken well, dug into the slope, with a number of well built steps leading down to it. Measurements are given as 27ins by 21ins. In 1894 it was described as being covered with slabs on which earth had been heaped. Ffynnon fair shares its dedication with St Mary's Church, Llanfair (NPRN 43887), some 260m to the south-west. A more ancient well, in ruinous condition and obscured by briars, was described as being located further downslope towards the church.

Sources include:
Richards, R and Lloyd, R G, 1894-5, Transactions of the cymmrodorion Society, 124

N Vousden, RCAHMW, May 2012