What appears at first to be a simple grassy mound resolves, on closer inspection, into a carefully engineered enclosure: a circular area roughly thirty metres across, shaped by a combination of an earthen bank, a scarp, and a shallow fosse, which is a defensive ditch dug around the perimeter. A gap in the bank to the south most likely marks the original entrance.

Ringforts, known in Irish as ráth when they are earthen rather than stone-built, are among the most common archaeological monuments in Ireland, with tens of thousands recorded across the island. They date primarily from the early medieval period, roughly the fifth to twelfth centuries, and functioned as enclosed farmsteads, the home of a single family or small community, with the bank and fosse serving to mark territory, deter cattle raiders, and keep livestock in as much as to keep threats out. The Breeny More example follows the classic form: a roughly circular enclosure defined by a bank standing about one and a half metres high on the northern and western arc, transitioning to a scarp, a steep natural or cut slope, on the western to northern side, with the fosse running from the north-north-east around to the south. That combination of bank, scarp, and fosse suggests the builders were working with and adapting the natural slope of the ground rather than imposing a uniform geometry on it.