Wedge tombs are the most numerous megalithic tomb type in Ireland, generally dating to the late Neolithic and early Bronze Age, and they take their name from a characteristic shape: wider and taller at the west end, tapering toward the east. This one at Caherbirrane follows that pattern faithfully, or did once, before time and the boggy ground had their way with it.

Early accounts recorded a gallery roughly two metres long, about a metre wide at its western end and narrowing to around eighty centimetres at the eastern end, oriented along an east-west axis. At the western end sat a septal stone, a dividing slab set across the interior, preceded by a short portico, a kind of forecourt or antechamber formed by upright stones at the entrance. The whole structure was roofed by a single large stone, which now lies displaced. The details come from the survey work of Ruaidhrí de Valera and Seán Ó Nualláin, published in their 1982 volume covering the megalithic tombs of Cork, Kerry, Limerick, and Tipperary, which remains a foundational reference for this class of monument in the south of Ireland.