That hollow, roughly 5.7 to 5.9 metres wide and about a metre deep, is not the work of excavation but of gradual plunder; the stone was robbed out over generations to build the field walls that now abut the cairn on its south-eastern and north-eastern sides. It is a common enough fate for prehistoric monuments in Ireland, where a conveniently mounded supply of loose stone has always been hard to resist, but the result here is a structure that carries its own dismemberment as part of its visible form.

The cairn measures 18.3 metres across and rises between 1.77 and 2.15 metres, making it a substantial presence even in its depleted state. It sits enclosed within a hillfort, a type of monument in which an elevated site is defined and defended by one or more banks and ditches, and the two together suggest this hilltop held significance across more than one period of prehistory. Knockadiggen is visible to the north-east from the summit, and the position commands panoramic views in all directions, which is typical of cairns of this kind, whether they served as burial monuments, territorial markers, or both.

Forestry has crept up to the cairn's southern and north-western edges, but a corridor has been left open through the trees, preserving a clear vista to the south-west. That deliberate gap is a small, practical concession to a monument that has otherwise had to look after itself.