What survives is essentially a cartographic ghost: a curved line recorded on an Ordnance Survey large-scale plan, suggesting something that was already disappearing when the surveyors passed through, and has since vanished entirely from the ground.

The OS 1:2500 plan, surveyed between 1912 and 1916, captured a field boundary arcing from east, through south, to north-north-west. Had that curve continued to close on itself, it would have described an almost circular area of roughly 30 metres in diameter, the kind of dimensions consistent with an early enclosure, the term used for a broad range of circular or sub-circular enclosed spaces found across Ireland, from prehistoric settlements to early medieval farmsteads. A second boundary, running north-north-west to south-south-east, cut across the arc at two points, interrupting whatever coherence the original shape once had. Whether that later boundary was responsible for erasing the enclosure, or simply recorded its already fragmented state, is impossible to say now. No surface trace survives at Allykeolaun today.

What makes this site quietly interesting is precisely its absence. It is documented not because something stands, but because someone drew a line on a map over a century ago, and that line preserved the outline of a structure that the landscape itself has since swallowed. The high ground setting, overlooking the valley to the south, is a position typical of enclosed sites throughout the west of Ireland, chosen for visibility and drainage rather than by accident. Without that early twentieth-century survey, the enclosure at Allykeolaun would exist in no record at all.