These sites, known in Irish as cillíní (singular: cillín), were a quiet but widespread feature of the rural Irish landscape for centuries. Unbaptised infants could not, under Catholic doctrine, be interred in consecrated ground, and so families buried them instead in marginal spaces: old ringforts, field boundaries, coastal dunes, and enclosures like this one. The practice continued well into the twentieth century, and the sites tend to be treated with a particular kind of private reverence, neither well-marked nor entirely forgotten.

The enclosure at Tullahennel is roughly circular, with an internal diameter of around 41 metres north to south and an external diameter of 57 metres. The enclosing earthen bank is notably wide at its base, measuring about 12 metres across, though it rises only modestly, between 0.3 and 0.9 metres on the interior face and around 0.6 metres on the exterior. A low ridge roughly 3 metres wide runs east to west across the interior, and may be the remains of an earlier field boundary incorporated into the site. The 1841 to 1842 Ordnance Survey map shows a small bohareen, a narrow rural laneway, that appears to have led up from the south-west, circled the enclosure, and exited to the north-west. No trace of that path survives on the ground today, which gives some sense of how quietly this kind of landscape feature can be absorbed and erased over the course of a few generations. The site was documented as part of the North Kerry Archaeological Survey published in 1995 by C. Toal.