This is a rath, a type of enclosed farmstead built in early medieval Ireland, typically consisting of a raised bank of earth surrounding a domestic interior. Most were constructed between roughly the sixth and twelfth centuries, and tens of thousands once existed across the country. What makes any individual example worth pausing over is what time and land use have done to it, and how much of the original form persists.

Rathbaun, as the site was already named on the Ordnance Survey six-inch map of 1838, is a roughly circular raised area measuring approximately 24.6 metres north to south and 24 metres east to west. Its enclosing earthen bank survives in degraded form, three and a half metres wide in places, with an exterior height reaching 1.5 metres on the southern side. A few stones protrude along the top of the bank. The interior is broadly level, though the eastern half slopes gently down towards a gap of around 5.5 metres in the southern bank; this slumped opening may mark where the original entrance once stood. The southern face of the bank has been absorbed into a later field boundary, remnants of which continue eastward beyond the rath itself, suggesting the monument was treated as a convenient ready-made boundary at some point in the post-medieval period. A gravel quarry pit, visible on the 1922 Ordnance Survey map, once came to within a metre of the western bank, a close call that left a real mark on the site's western edge, though the pit is now disused and grassed over. A stream runs approximately 150 metres to the south, and a farmyard sits close by to the north-west, meaning the rath is now folded into a working agricultural setting that has been pressing against it, in one form or another, for quite some time.