What gives Cloonnagalleen its particular interest is the way it uses the landscape itself as part of its own boundary. Rather than being defined entirely by built or dug features, the enclosure takes advantage of a dry valley's steep western edge to form one side of its perimeter, reserving human effort for the sections where nature offered no such shortcut.

The site was recorded by Denis Power and uploaded to the national record in August 2011. It sits at the upper western edge of a dry valley, a type of landform shaped by water action in the past but no longer carrying a stream. The enclosure measures roughly 18 metres on its north-northwest to south-southeast axis and about 11 metres across, east to west. Where the valley drop does not provide a natural boundary, a wide, shallow fosse takes over. A fosse is simply a ditch, typically dug to define or defend a space, though the one here is more subtle than dramatic: it measures around 8.25 metres wide and only half a metre deep, suggesting enclosure and demarcation rather than any serious defensive intent. Whether it was used for agricultural purposes, to pen animals, or served some other function is not recorded in the available notes.

The site lies in ordinary farmland, so access would require permission from the landowner. The earthwork itself is the kind of feature that rewards a careful eye rather than a dramatic reveal; the fosse is shallow enough that it might read at first as a gentle dip in the ground, and the valley edge that forms the western boundary is more pronounced than any constructed element. Early morning or low winter light tends to pick out subtle earthworks more clearly than the flat brightness of a summer afternoon, as raking light casts shadows across slight changes in ground level. The Irish landscape holds a great many such enclosures, and part of their quiet appeal is precisely that they are so unassuming, demanding a certain patience before they give themselves away.