What was once a clearly defined circular embanked enclosure, roughly 25 metres across, appears on the 1838 Ordnance Survey six-inch map with enough confidence to be recorded. By the time later map editions were produced, it had vanished from the cartographic record entirely, replaced by an unremarkable rectangular field plot. The enclosure did not actually disappear, of course. It was absorbed, adapted, and overwritten by the ordinary business of farming.

An embanked enclosure of this kind is a broad category in Irish archaeology, encompassing everything from early medieval ringforts, which were the fortified farmsteads of Gaelic Ireland, to enclosures of prehistoric origin whose function remains genuinely uncertain. At Ballinlag, the original circular form has been incorporated into a sub-rectangular field plot measuring roughly 40 metres east to west and 20 metres north to south. Careful fieldwork has picked out what the maps no longer show: a sunken road skirting the south side follows the gentle curve of the original enclosure rather than cutting across it, suggesting the old boundary was never entirely erased but simply put to new use. A scarp roughly a metre high, curving from the northwest to the east, may preserve the arc of the original bank, and a short section at the northeast appears to retain an internal lip consistent with the remains of that bank, which was perhaps 2.5 to 3 metres wide. Traces of stone facing survive on the scarp, though these are thought to belong to its later life as a field boundary rather than to the original construction.

The interior offers its own complications. The ground level shifts unevenly across the enclosed space, the central area being somewhat raised, and a narrow linear rise running east to west may be the ghost of a former wall or fence. Dense blackthorn scrub, particularly in the southern half, made close examination difficult, leaving some of these questions genuinely open. To the north the ground drops towards wet boggy ground; to the south and southwest a stream valley opens up. A disused railway track lies about 200 metres to the east, a reminder that even landscapes that look timeless carry several distinct pasts layered within them.