The site at Lisnanard is a cashel, a type of ringfort built from dry-stone walling rather than earthen banks, and this one has collapsed so thoroughly over the centuries that no facing-stones remain visible and no original entrance can be identified. What survives is an oval platform of rubble, measuring roughly 43 metres north to south and 39 metres east to west, its walls reduced to a low, spread bank somewhere between 0.8 and 1.1 metres high and up to 6.8 metres wide. The thorn cover that now smothers the site makes it genuinely difficult to access, let alone to read as a coherent structure.

The townland name preserves the memory of the fort more clearly than the fort preserves itself. It appears as Lisnanard on the 1915 edition of the Ordnance Survey six-inch map, a name that translates roughly from the Irish Lios na nArd, meaning something like the fort of the heights or the high place. The feature was already being recorded cartographically as far back as 1842, when it was hachured on the first Ordnance Survey edition, indicating a recognisable earthwork even then. It is understood to be the feature from which the townland took its name, making it older than the administrative boundaries that now contain it, though the wider landscape context is suggestive of a busy early medieval presence. About 450 metres to the east lies a cluster of related sites: two raths, which are earthen-banked ringforts, and a further enclosure, all part of what is sometimes called the Ballyvaghan forts group. That density of settlement within a relatively small area points to a landscape that was carefully organised and intensively occupied, even if what remains above ground is now fragmentary and overgrown. Adding a layer of complexity, later field walls were at some point constructed across both the northern and western portions of the cashel's interior, suggesting the site was reused or simply incorporated into post-medieval agricultural arrangements long after its original function had been forgotten.