These sites, known in Irish as cillíní (singular: cillín), were used for the interment of unbaptised infants and others considered ineligible for burial in consecrated ground under Catholic Church practice. They occupy a particular and melancholy position in Irish social history, located at the margins of official religious life and, often, at the margins of the landscape itself, tucked into field corners, old ringfort banks, or the edges of bogs.

The use of cillíní was widespread from the medieval period through to the mid-twentieth century, though the practice declined significantly after the loosening of Church strictures around burial rites. The locations were rarely formally recorded and were passed on through local knowledge rather than written documentation. Many have been lost entirely, while others survive as low, unmarked mounds or enclosures that are easy to walk past without recognition. The Treanmanagh site is recorded as a monument, which indicates it has been identified and noted as a place of archaeological and historical significance, even if detailed information about its precise character and condition remains limited at present.