The feature is a rath, the most common type of ringfort found across Ireland, built as an enclosed farmstead during the early medieval period. What marks this one out is its modesty: a circular area roughly 32 metres across, defined by an earthen bank rising only about 0.6 metres, with a shallow external fosse, or ditch, running from south-southwest to north around the perimeter. The bank is overgrown now, blending into the surrounding grassland in a way that makes it easy to overlook unless you know what you are looking for.

Ringforts were domestic enclosures, typically constructed between the sixth and tenth centuries, used by farming families to define their homestead and provide a degree of protection for livestock. The earthen bank and accompanying fosse at Summerhill follow a familiar pattern: earth dug from the fosse was piled inward to form the raised boundary. The site was recorded as part of an archaeological survey of the Ballinrobe district, covering the areas around Lough Mask and Lough Carra, published in 1994. That survey catalogued it as number 215, placing it within a broader landscape already known to be rich in early medieval settlement activity, given the proximity of those two significant lakes and the fertile lowlands between them.