The enclosure is a rath, a type of ringfort built in early medieval Ireland, typically as a defended farmstead surrounded by one or more earthen banks and ditches. This one, however, acquired a second life over the centuries as a place of burial for children, and the ground inside it gives no outward sign of what it contains. There are no headstones, no mounds, no markers of any kind visible at surface level.

The practice of burying unbaptised children, or infants who died before receiving any rites, in marginal or liminal ground was once widespread across Ireland. Church law historically excluded such children from consecrated cemeteries, and so communities turned to other places, often ancient, already set apart from ordinary land. Raths, regarded with a mixture of reverence and unease as the dwellings of the fairy folk, occupied a curious position in the landscape, neither fully secular nor sacred in a Christian sense. They were, in their way, already the property of something else. According to local information, the interior of the rath at Bulcaun served this purpose into living memory, with the last two burials recorded as taking place in the early twentieth century.

The absence of any visible grave markers is not unusual for sites of this kind, known in Irish as cillíní. Burials were often shallow and unmarked, sometimes indicated only by a small stone or nothing at all. What makes Bulcaun quietly affecting is the layering of time compressed into a single patch of ground, an earthwork that predates the Norman arrival by centuries, repurposed again and again by communities who needed a place for those who could not lie in the churchyard.