This is a ring-barrow, a type of funerary monument built during the Bronze Age, in which a central burial mound is encircled by a flat-bottomed ditch, known as a fosse, and then by a raised outer bank beyond that. The whole structure measures roughly 21 metres across, which is modest on the ground but represents a considerable investment of labour for a community burying its dead sometime in the prehistoric past.

The mound at the centre has a flat top and steep sides, rising between 0.8 and 1.25 metres above the fosse floor, though it sits only about 0.25 metres above the surrounding pasture on its outer edge, giving it a subtler profile than its internal structure suggests. Surrounding it, the fosse runs between 1.8 and 2.3 metres wide, and the outer bank beyond that is broad and almost flat-topped, between 3.7 and 5 metres across. The southern side of the central mound has been disturbed by digging at some point, a common fate for monuments of this kind, where later generations cut in hoping to find valuables. The monument was recorded on the Ordnance Survey 25-inch plan of 1897 and again on the 6-inch edition of 1920, confirming it was visible and mappable for well over a century before modern survey work caught up with it. What makes the Doonnagore location particularly notable is that this barrow is not alone: a second ring-barrow sits approximately 12 metres to the east, and a third lies around 100 metres to the north-north-east, suggesting this coastal pasture was once a deliberate focus for burial and perhaps for the marking of territory or ancestry in the landscape.