A fosse is simply a ditch, here roughly three metres wide, and together with the low earthen bank it forms a boundary that has been worn down over centuries to the point where it is only detectable at the eastern and western ends. The northern boundary fares better: a semi-circular stone wall still stands to an internal height of one and a half metres, dropping to under a metre on the exterior face, with walls nearly half a metre thick. The whole platform measures roughly 25 metres north to south and just over 35 metres east to west, a modest scale that makes it easy to underestimate.

Enclosures of this type are scattered across Ireland and served a range of purposes depending on period and context, from settlement boundaries to ritual or agricultural use. What makes this one at Lisnalurg quietly interesting is its position. Placed on high ground with extensive views in all directions, the siting suggests that whoever built and used it valued visibility, whether for watching over land, signalling, or simply the practical advantages of elevated ground in a working landscape. Two stone pillars standing immediately south of the stone wall are visible today but are considered unrelated to the enclosure itself, a small detail that underlines how the site has accumulated features over time that belong to different moments and different hands.