The font from the old church at Ballybacon, in County Tipperary, is something of an outlier: it is rectangular, both inside and out, a shape that accounts for no more than a quarter of all known Irish examples, the overwhelming majority of which turn up in England instead. That alone would make it worth noting, but the carved decoration on its four granite faces gives it a quiet visual authority that goes beyond the merely unusual.

The font is cut from fine-grained granite and decorated in relief on every exterior face. Three of the four sides carry the same design: three large leaf motifs arranged around a pair of triangles. The fourth side shifts to something more floral, with two six-petalled flower forms separated by two triangles placed apex to apex. The interior basin measures 0.45 metres by 0.34 metres, with a flat bottom, a central drain, and a rim five centimetres wide. On the underside there is a circular depression roughly 32 centimetres across and up to two centimetres deep, which may indicate that the font was originally mounted on a base or column. Cahill and Twohig, writing in 1976, examined the question of dating carefully. Square or rectangular fonts were fashionable in England during the eleventh and twelfth centuries, but research by Helen Roe pointed toward a mid to late thirteenth-century date for this piece, placing it closer in time and character to a group of fonts from the diocese of Ossory assigned to the same period.

The font spent centuries in the open grounds of the ruined Ballybacon church, and by the 1970s that exposure was considered to be causing damage. In 1975 it was moved to the present Ballybacon church, situated a few hundred yards to the north-west of the old ruin, in the townland of Garryduff. It is there, in active rather than abandoned surroundings, that the font now sits, its carved panels still legible after more than seven hundred years.