These sites, known in Irish as cillíní (the singular is cillín), were used for the interment of unbaptised infants and others considered, under Catholic doctrine, ineligible for consecrated ground. They occupy a peculiar space in Irish religious and social history: neither fully sacred nor entirely ordinary, they tend to sit at boundaries, literal and symbolic, often at the edges of fields, beside old ringforts, or in marginal land that seemed to belong to no single world.

The practice of burying unbaptised children apart from the community cemetery was widespread in Ireland from the medieval period through to the mid-twentieth century, driven by the theological concept of limbo and the pastoral structures that reinforced it. Families who lost a newborn before baptism, or before a priest could be reached, had little choice but to find a separate resting place. Cillíní were sometimes ancient, repurposed from pre-Christian enclosures or early medieval ecclesiastical sites, lending them a layered quality that archaeologists and folklorists have found difficult to untangle. The Lisdeen example sits within this broader tradition, though specific details about its age, extent, or any associated features remain largely undocumented in publicly available sources at this time.