The site at Summerhill is a rath, the commonest type of ringfort in Ireland, essentially a circular area of ground defined by an earthen bank and a surrounding ditch, known as a fosse. These were the farmsteads of early medieval Ireland, roughly from the fifth to the twelfth centuries, where a family and their livestock would have lived within a low but legible perimeter. What makes them easy to overlook today is precisely how thoroughly they have been absorbed into the ordinary countryside.

This particular example measures forty-five metres across in both directions, making it a fairly typical specimen in terms of scale. The enclosing bank, which runs from the northern side around to the south-west, still stands to around 0.8 metres in height, though it is partly overgrown. Outside it, a shallow fosse survives at roughly 0.2 metres deep. More intriguing are two additional low earthen banks running from the western edge inward toward the centre of the site, measuring approximately 15.7 metres and nine metres respectively. Internal divisions of this kind within a ringfort can indicate subdivided use of the enclosed space, though what function these particular banks served remains a matter of inference rather than record. The details were recorded by D. Lavelle as part of an archaeological survey of the Ballinrobe district, published in 1994 by the Lough Mask and Lough Carra Tourist Development Association.

The site sits in good pasture on a gentle east-facing slope, which means it remains farmland and reads, at first glance, simply as a slight rise and dip in a field. The earthwork is there, however, if you know to look for the curve of the bank and the line of the fosse just beyond it, two faint arcs carrying the outline of an enclosure that was once the deliberate boundary of someone's world.