This is a rath, the most common type of early medieval enclosure in Ireland, typically built as a defended farmstead by a family of some local standing. Thousands survive across the country, many still unmarked on tourist maps, and this one at Kilmacar is among the more modest examples: roughly 28 metres east to west and 24 metres north to south, enclosed by an earthen bank that stands less than a metre high on the outside and a shallow external fosse, or ditch, that has largely silted to almost nothing.

What makes the site quietly interesting is its pairing of entrances. There are two gaps in the bank, each about three metres wide, one to the east and one to the west. In a rath, a single formal entrance was the norm, its orientation often deliberate, so the presence of a second opening is a small puzzle. The more likely explanation is practical: one gap is the original entrance and the other a cattle gap, added at some point to allow livestock easier movement through the enclosure. The interior, which continues to serve as pasture and shows the characteristic ground disturbance caused by hooves, slopes gently westward in line with the natural fall of the land. The valley opens out around it, with clear views north and south along the Gloshia and east across to the far side, the kind of sightlines that would have mattered to anyone choosing where to settle.