Roughly a metre high and covering an area of about four by five metres, it occupies the northern portion of the field that local people have long called "Cillín Field", a name that carries its own quiet weight. A cillín, in Irish tradition, is typically a small, unconsecrated burial ground, often used for unbaptised infants or others excluded from churchyard burial. Here, though, local memory preserves a rather more elevated association: the cairn is said to mark the resting place of a bishop.

The scholarly trail leads further back than local tradition alone. The site is likely identical with Cill Cromglaisi, a place mentioned in Crichad an Chaoilli, a medieval territorial tract of the Fermoy region. Patrick Power, writing in 1932, identified it as a place of unusual significance, noting references to it scattered across saints' lives and martyrologies, including an entry in the Martyrology of Donegal under the 11th of April. The location fits: the field lies beside an ancient ford of the River Funshion, a crossing that would have given the site both practical and symbolic importance in early medieval Ireland. Power also drew on the Life of Finchu, an early Irish saint's life, which records that Cairbre, a king of Munster, was fostered by a figure named Sgeallan Ceal of Cromglaisi and was subsequently buried at this very place. A fostering relationship in early Irish society was a close and politically significant bond, and the burial of a king at a site associated with his foster father would not have been incidental.