A rath, to use the Irish term, is a roughly circular enclosure defined by an earthen bank and, often, an outer ditch; thousands of them survive across Ireland, the remnants of enclosed farmsteads and high-status residences from the early medieval period. This one measures approximately forty metres north to south and thirty-three metres east to west, making it a reasonably substantial example of the type. The defining bank is much overgrown now, and several breaches have opened in it, most of them appearing to be of modern rather than ancient origin. The external fosse, the ditch that once reinforced the enclosure's defences, survives along the southern and western arc.

What gives this site its particular character is its situation and its neighbours. The slope it occupies opens eastward, and from that orientation the outline of Glinsk Castle is visible to the north-east. Glinsk is a well-known seventeenth-century tower house in north Galway, associated with the Burke family, and its presence on the horizon from this earlier earthwork creates an accidental layering of the landscape, two different kinds of fortified dwelling separated by centuries but sharing the same stretch of country. To the south lies a further enclosure, a separate archaeological feature that suggests this part of Ballynakill was not lightly settled. The rath itself belongs to a much older tradition than the castle beside which it sits in the view, almost certainly predating it by at least half a millennium.