What you are looking at is almost certainly a bawn, the walled or embanked enclosure that once surrounded and defended an Irish tower house or castle. Most bawns were built of stone and have long since been robbed out for field walls and farm buildings; this one, made of earth and stone, has survived in a different form, flattened and grassed over but still legible in the landscape if you know what to look for.

The enclosure measures roughly 60 metres on its northeast to southwest axis and 45 metres northwest to southeast, and it is bivallate, meaning it has two concentric banks separated by a fosse, or ditch, running between them. The inner bank is the more substantial of the two. Along the straight southwestern side and around to the north and northeast, the earthwork is relatively well preserved. Towards the east and southeast, however, it becomes a low, wide grassy ridge, considerably worn down, and this degraded section may point to where an original entrance once stood. Rathdrishoge Castle stands along the southwest side of the enclosure, its position consistent with the idea that the earthwork once formed the defensive perimeter of its grounds. The site was described in these terms as far back as 1978, suggesting it has been recognised as something more than a natural feature for at least several decades.