Roughly ten metres across and five metres deep, it is now largely swallowed by briars and bushes, its interior invisible to the casual eye. Local knowledge identifies it as a cillíneach, the Irish term for an unofficial burial ground used for unbaptised infants and others who, under Catholic practice, could not be interred in consecrated ground.

Cillíní (the plural form) are found across Ireland in their hundreds, occupying liminal spaces: field boundaries, coastal margins, the edges of ancient raths or ringforts. The theological reasoning that produced them, the doctrine that unbaptised souls could not enter heaven, placed grieving families in an impossible position, and so communities quietly set aside places like this one in Ardagh, where the unbaptised could be laid to rest with some dignity if not with official sanction. The enclosure here is defined by a field boundary on its northern side and a stone wall about a metre high on the remaining sides, a modest but deliberate boundary between this ground and the ordinary pasture surrounding it. The wall's survival, and the preservation of local memory about the site's purpose, is itself notable given how thoroughly many such places were forgotten or absorbed into working farmland.