Fonts of this kind, used for the sacrament of baptism, were typically freestanding features of a church interior, so finding one built into a window recess hints that somebody, at some point, decided that safety mattered more than convention.

Writing in 1905, the historian Carrigan documented the font in some detail, noting that it was fashioned from freestone and cut into an octagonal form, with the corners chamfered, meaning the edges were angled off rather than left square, giving the stone a refined, considered finish. Ornamentation runs along the top surface of the rim, and the round bowl, just under half a metre wide and roughly twenty centimetres deep, retains a small drain hole at its centre. Carrigan also observed traces of an iron hinge, the remnant of a lid that once covered the bowl, a common feature of medieval fonts intended to prevent the consecrated water inside from being tampered with or misused. Later measurement gives the overall width of the piece as 0.56 metres, sitting on a low circular sandstone pedestal just nine centimetres high. The whole object is compact, almost modest in scale, yet the quality of its cutting suggests it was made with some care and skill.

The font sits within a multiperiod church site at Coolaghmore, meaning the ecclesiastical remains there represent more than one phase of building and use across the centuries. The font itself, with its chamfered octagonal body and lidded bowl, is broadly consistent with late medieval Irish ecclesiastical stonework, though its precise date has not been firmly established. What endures is the detail: the worn iron hinge socket, the central drain, and the ornamented rim, each small feature carrying the trace of a very ordinary and very ancient ritual.