Most striking is a sandstone block standing roughly a metre tall, sitting 2 metres inside the northern bank, its shape irregular and its placement oddly deliberate. Near the south-south-west edge of the enclosure, two upright stones are aligned east to west. Neither feature is easy to explain away as purely functional, and both sit quietly in a field that might otherwise seem unremarkable.

Ringforts, known in Irish as raths when defined by earthen banks, were the most common form of rural settlement in early medieval Ireland, typically serving as enclosed farmsteads between roughly the fifth and twelfth centuries. The one at Carrigdangan follows the general form: a roughly circular enclosure, about 24 metres north to south and 21 metres east to west, bounded by an earthen bank standing about a metre high along its western to southern arc, and a much more pronounced scarp, rising to 2.6 metres, everywhere else. The bank is stone-faced along the north-west to south-south-east stretch, and there is a deliberate gap facing south-south-west, likely the original entrance. Because the site sits on a slope, the interior has been built up on the south-west side to create a more level surface, a practical adjustment that would have taken considerable effort. Faint traces of cultivation ridges, running roughly north-north-east to south-south-west, are still visible across the interior, suggesting the enclosed ground was worked at some point, though whether contemporaneously with the fort's main occupation or in a later phase is unclear.