It is just twenty centimetres high, less than two metres wide, and roughly three and a half metres long, oriented north to south. And yet it is a cairn, a deliberately built stone mound of the kind that appears across the Irish countryside in contexts ranging from prehistoric burial to simple field clearance, and whose precise purpose is not always easy to determine.

What is known about this particular cairn comes from a heritage assessment carried out in 2010 by archaeologists Quinn and Carroll, who surveyed the area around Doonens, Co. Cork, as part of an appraisal for a proposed wind farm. The cairn at An Inse Mhór was noted alongside at least two comparable examples in the same area, described simply as cairns 1 and 7, all of them sitting within portions of cut-away bog. Cut-away bog refers to land from which peat has already been extracted, often leaving an altered and somewhat exposed terrain. The stripping back of that peat cover can bring stone features into clearer view, which may explain why several cairns were identified in relatively close proximity during the survey. Whether these mounds mark something older beneath the ground, or represent more practical historical activity such as stone clearance during agricultural use of the land, the available record does not say.