Cairns of this kind are prehistoric stone mounds, raised over burial chambers or as territorial markers, and this one at Cloghleagh retains enough of its original form to reward close attention. Twelve metres across and rising to about one and a half metres, it is not enormous by the standards of Irish passage tombs, but the survival of the internal chamber makes it more than a shapeless heap of stones.

The chamber, located just south of the cairn's centre, measures roughly one and a half metres long and stands about one and a half metres high. A large slab forms its northern wall, while the eastern side is constructed from drystone walling, the technique of fitting stones together without mortar. The cairn does not sit in isolation. To its east lies another cairn, and to its north an enclosure, suggesting this stretch of Wicklow hillside was a focus of some sustained prehistoric activity rather than a single, incidental monument. The peat that now partly covers the cairn has, in one sense, done the structure a service, slowing erosion and preserving details that exposure to weather alone would have obscured.