A roughly circular hollow, around 23 metres across, marks the western edge of a field boundary on a north-northwest-facing slope in County Cork. The structure has been levelled, most likely by centuries of agricultural use, leaving only a depression in tillage land where an enclosed farmstead once stood.

A rath is the Irish term for a ringfort, the most common archaeological monument type in Ireland. These were typically circular enclosures defined by an earthen bank and outer ditch, used as defended farmsteads during the early medieval period, roughly from the fifth to the twelfth centuries. They were places of daily life, livestock, and household activity rather than military fortifications in any grand sense. The example at Gaggan would have commanded a wide open view to the west, north, and northeast, a practical advantage for a farming community keeping watch over land and animals. That same vantage point is still there, even if the earthworks themselves are not.