Three of them are spaced just two metres apart, arranged in the form of an equilateral triangle. The fourth lies roughly twenty metres to the south-west, absorbed into a field boundary, as though the landscape eventually just grew around it.

These are boulder burials, a monument type found almost exclusively in the south-west of Ireland and concentrated heavily in County Cork. The form is simple but imposing: a large, often massive, flat or rounded boulder is raised on a small number of support stones, covering what is presumed to be a burial deposit beneath. At Derrymihin, the cover-stone of the eastern monument in the triangular group measures 2.2 metres by 1.6 metres and sits nearly a metre thick, supported on three visible stones beneath. The northern monument carries a slightly smaller cover-stone, 1.7 metres by 1.3 metres, resting on two supports. The western monument, with a squarish cover-stone of 1.5 metres by 1.5 metres, has a single visible support stone. The fourth burial, now partly built into the field fence, has a cover-stone measuring 1.9 metres by 1.7 metres, also on two supports. The grouping of three monuments in a deliberate geometric arrangement is particularly unusual; most boulder burials are encountered singly or in loose pairs, and a triangular cluster of this kind suggests a level of planning that complicates any simple reading of these structures as purely functional. Scholars, including Seán Ó Nualláin, who catalogued the site in 1978, have noted it among significant examples of the type in West Cork.