These sites, known in Irish tradition as cillíní or cilliní, were set aside for unbaptised infants and others considered to exist outside the formal boundaries of the Church, including stillborn babies, and sometimes suicides or strangers. The one at Gortnamucklagh was significant enough to be marked on the Ordnance Survey six-inch map of 1842, labelled plainly as a Children's Burial Ground, which at least gives it a kind of official acknowledgement even if it remained outside the parish record.

The ground itself is irregular in shape, its boundary defined by a natural scarp that has been reinforced with dry-stone walling running from the north-east around to the south. Dry-stone construction, which uses no mortar, was the practical and traditional method for field boundaries and enclosures across rural Ireland, and here it serves to hold and mark the edge of the burial area against the slope of the land. Within this modest enclosure, many low grave markers have been recorded. These would typically be small, undressed stones placed flat or upright, with no inscriptions, reflecting both the informal nature of these burials and the grief that accompanied them, quiet and largely unrecorded.