These places, known in Irish as cillíní (singular: cillín), were used for centuries to inter unbaptised infants, stillborn babies, and others considered ineligible for the rites of the Catholic Church. They were not marked with headstones in any formal sense, and they were rarely spoken about openly. Their presence in the landscape was understood rather than announced.

Cillíní are found across Ireland in their hundreds, tucked into the corners of fields, along townland boundaries, beside ancient ringforts, or on the margins of older, pre-Christian burial sites. The choice of location was rarely arbitrary. Many were placed at liminal points in the landscape, on thresholds between the known and the uncertain. The practice of burying unbaptised children separately from the main churchyard persisted well into the twentieth century in some parts of rural Ireland, shaped by theological rules that denied such children a place in heaven and, by extension, in the consecrated ground of a parish cemetery. The grief attached to these sites was real, but it was often carried privately, without public ritual or memorial.