It measures roughly ten centimetres wide and thirteen centimetres tall, with a flat face, pronounced eyebrows, a flat nose, and a small circular mouth. Weathered by centuries of exposure, it has the blunt, compressed quality common to medieval stone carving in Ireland, where the intention was rarely naturalism but something more fixed and emblematic.

The head sits in the yard of Williamstown House, about twenty metres south of the site of Williamstown Castle and its associated bawn, the term for the walled enclosure that typically surrounded an Irish tower house, offering protection for livestock and household dependants. The proximity is almost certainly not coincidental. It is thought the carved head may originally have come from the castle itself, displaced at some point during the long process of decay, demolition, and reuse that accounts for so much of what survives from medieval buildings in rural Ireland. Stone from abandoned structures was routinely incorporated into later farm buildings, walls, and houses, which is why carved fragments occasionally turn up in unexpected settings, repurposed as ordinary building material with no particular ceremony.