Known in Irish tradition as cillíní (singular cillín), these were informal burial plots, set apart from consecrated ground, where unbaptised infants and sometimes others excluded from the rites of the Church were quietly interred. They tend to occupy liminal spaces: the edges of townlands, ancient earthworks, or, as here, the margins of a demesne. Their presence is rarely announced, and they are easy to walk past without knowing what the ground once held.

The practice of burying unbaptised children outside consecrated cemeteries was rooted in Catholic doctrine as it was understood and applied in Ireland for several centuries. Without baptism, an infant was held to be excluded from heaven, and by extension from the churchyard. Families, left with few options, turned to places already perceived as old or set apart, locations that carried some residual sense of sanctity or at least of threshold. Demesne land, with its long history of occupation and its layered ownership, sometimes provided exactly that kind of margin. Cleaveragh itself sits on the outskirts of Sligo town, and the presence of a cillín within its grounds suggests that the site served local communities in ways that went well beyond its function as a landed estate.

Because the source material available for this particular site is limited, much of its specific history, including when it was last used, how it was marked, and how many children may be buried there, remains unrecorded in accessible form. What is known is that it is a recognised archaeological monument, which at minimum places it within a long tradition of informal burial that was quietly commonplace in Ireland until well into the twentieth century. These grounds deserve a certain kind of attentiveness from anyone who encounters them.