These were informal, unconsecrated burial places used for unbaptised infants, and sometimes for others considered outside the boundaries of formal Catholic burial, including stillborn children, strangers, and the unbaptised poor. For centuries, families who could not secure a church burial for their child would carry the small body to one of these quiet, liminal spots, often at the edges of fields, beside old walls, or within the bounds of earlier, pre-Christian enclosures. The demesne setting at Ballycurrin adds a particular texture to the site, placing this vernacular funerary tradition within a landscape that was also shaped by landed estates and the social hierarchies they imposed.

Cillíní are found in their hundreds across Ireland, and Mayo has a notable concentration of them. The practice of burying unbaptised children separately from consecrated ground reflected the theological position, long held in Catholic doctrine, that those who died without baptism could not enter heaven in the conventional sense. Families nonetheless marked these graves with care, often using small stones, and returned to them across generations. The grounds of a demesne like Ballycurrin, with its layered history of land ownership and agricultural change, would have provided a space that sat outside ordinary parish boundaries in more ways than one. The specific history of this particular cillín, including when it was last used and by which local families, remains to be fully documented.