It measures roughly four metres by three and a half, near-square in plan, with a narrow entrance cut into the north wall and a modern altar and plaque set against the east. The name Aharla points, etymologically, towards a burial ground, yet no graves have ever been found here. The structure carries its meaning loosely, gesturing at something without quite revealing it.

What makes the place stranger still is the cluster of local names attached to it. It is also known as Leaba Rónáin, meaning the bed of Rónán, and Teaghlach Rónáin, the household of Rónán, both of which tie it to the early Christian saint after whom Cill Rónáin itself is named. Scholars including Westropp, writing in 1895, and Robinson in 1980, have suggested the enclosure may sit on or very close to the site of Rónán's early medieval monastery, though nothing of that foundation has been identified or excavated. The north wall and portions of the south have been rebuilt at some point, so what survives is partly reconstructed. Around forty-five metres to the west, a holy well was once recorded in association with the site; holy wells in Ireland were typically places of local veneration, often linked to a named saint and visited for healing or prayer. That well appears to have left little visible trace today. The result is a place that accumulates associations, burial ground, monastic site, saint's resting place, without firmly being any of them.