Far fewer notice that somewhere in the plantation forestry nearby, among the conifers on a slight ridge overlooking the glen between Cruagh and Mountpelier, there is a megalithic tomb old enough to make the eighteenth-century lodge look freshly built. The structure is stripped and incomplete, its roofing slabs long gone and its cairn material dispersed, yet it remains legible as a monument if you know what you are looking at.

The tomb belongs to a class known as wedge tombs, the most numerous type of megalithic monument in Ireland, generally dated to the late Neolithic and early Bronze Age. The defining characteristic of the type is a gallery that tapers in both height and width from front to back, usually oriented with its wider, taller entrance facing west or south-west. At Killakee, the chamber runs east to west, with a west-facing façade and entrance; the internal space measures roughly six metres in length and six metres in width. It is defined by sidestones and a single endstone, and running parallel to the outer faces of those stones are the remains of a double revetment wall, a second skin of upright slabs that would originally have helped retain the cairn and given the monument its outward bulk. Traces of kerbstones survive in the north-west. The tomb was documented by Ó hÉailidhe in 1978, whose survey recorded the irregular low mound as seven metres across.

Access is on foot through the forestry, and the plantation setting means the monument is easy to miss amid the dense growth and uneven ground. The glen between Cruagh Mountain and Mountpelier provides a rough orientation. The roofing slabs and cairn material have been removed at some point, so what remains is a low scatter of upright and displaced stones rather than anything immediately dramatic. Looking for the protruding slabs and the parallel lines of the revetment wall is more rewarding than expecting a conventionally imposing ruin. Autumn or winter visits, when the low sun angles in from the west and the undergrowth has died back, make the stonework easier to read against the ground.