The site centres on a possible rath, the term for a circular earthen enclosure typically dating from the early medieval period and associated with farmstead settlement, and at some point this particular one was repurposed as a children's burial ground. No grave markers survive inside the enclosure today, yet the ground once served a function that was common across rural Ireland for centuries: the unofficial burial of unbaptised infants, who were excluded from consecrated churchyards under Catholic practice and laid instead in liminal, unconsecrated places.

The earliest documentation of this use comes from a 1969 record by Aldridge, who noted the site's function as a children's burial ground. Such places are sometimes called cillíní, and they tend to occupy marginal or ancient ground, places already set apart from ordinary life, old ringforts, boundaries, shorelines. The physical evidence at Derrynabrock is subtle. Immediately to the south-west of the rath, a low and irregular heap of stones, roughly four to five metres at its widest, sits beside an ash tree. Local tradition holds that these stones may mark graves, and the ash tree itself, long associated in Irish folk belief with threshold and protective qualities, gives the spot a quietly charged atmosphere that the bare landscape does nothing to dispel.