The outer enclosure, a subrectangular area roughly fifty metres east to west and up to forty metres across at its widest, is built in what is called dump construction, meaning the wall was formed by piling stones rather than carefully coursing them. A smaller rectangular space, just under nine metres by seven and a half, is attached to its southern side. Together they suggest a layered history of human use, though much of that history remains unspoken.

What complicates the site is the presence of a children's burial ground within the enclosure. These sites, known in Irish as cillíní, were used across Ireland from the early medieval period well into the nineteenth and twentieth centuries as informal burial places for infants who died before baptism and were therefore excluded from consecrated ground. The name Killeenaskeagh itself likely preserves the word cillín, a small church or burial ground. Also found among the rubble is a fragment of a rotary quern, the kind of hand-operated stone used for grinding grain, a commonplace domestic object whose presence here hints at earlier settled activity on the site, though no further detail about its date or precise context has been recorded.