Known in Irish as a cillín (plural cilliní), these were informal burial places used for unbaptised infants, and sometimes for others considered ineligible for consecrated ground, including stillborn children, women who died in childbirth, and occasionally strangers or suicides. The Catholic Church's doctrine on limbo, which held that unbaptised souls could not enter heaven, meant that parishes would not permit such burials in churchyards. Families, left with few options, turned instead to marginal or liminal places: the edges of fields, old ringforts, coastal dunes, and ancient or abandoned enclosures.

Cilliní are found in their hundreds across Ireland, and Mayo has a particularly high concentration of them. They were rarely marked with headstones, and burials were often carried out at night or at dawn, quietly and without ceremony, which is part of why so many of these sites remain poorly documented. The grief attached to them was compounded by the absence of any formal rite. The Tiraninny site belongs to this broader tradition, a landscape of loss that was observed privately and passed down through local memory rather than recorded in any official register. Detailed records specific to this particular ground are not currently available, which is itself a kind of reflection of how these places were treated for centuries: acknowledged locally, overlooked institutionally.