The site at Gortnagap is a rath, the Irish term for a ringfort, a type of enclosed farmstead typically built during the early medieval period, roughly between the fifth and twelfth centuries. Thousands of them survive across Ireland, yet each one is its own puzzle of survival and adaptation, and this one has endured quietly in reclaimed grassland, its circular platform measuring approximately 42 metres north to south and 44 metres east to west.

What the ground preserves here is a roughly circular raised platform, its edges defined by a scarp, a slope or cut face in the earth, ranging from half a metre to one and a half metres in height. Beyond that, a surrounding fosse, essentially a ditch, runs to around two and a half metres wide and roughly 0.6 metres deep. There are faint traces of an outer bank as well, though whether this belongs to the original enclosure or to a later field boundary is uncertain. The entrance, a causewayed gap six metres wide in the eastern sector, is particularly interesting. It has been widened at some point to allow farm machinery through, yet the positioning and form suggest it follows the line of the original opening used by whoever lived here more than a thousand years ago. The valley itself opens up generous views to the east, south, and west, a detail that would not have been lost on an early medieval farmer choosing where to build.