What was once a circular rath, a type of enclosed farmstead built and occupied roughly between the fifth and twelfth centuries, survives here in a compromised but still legible state. Its diameter runs to around 33 metres, and though the monument has been worn down by time and farming, the basic grammar of its design remains: two earthen banks with a fosse, or ditch, running between them, a defensive arrangement typical of the more substantial ringforts built to protect a family's home and livestock.

The site at Gortnahorna shows how thoroughly later land use can reshape an ancient feature without entirely erasing it. A field bank, probably laid out at some point during the historic period to divide agricultural land, now runs directly over the inner bank from the north around through the east to the south-east, obscuring that arc of the original structure. On the opposite side, from south-south-west round to the west, the fosse and outer bank have fared somewhat better and can still be made out in the ground. A gap of about two metres at the north may be an original entrance, the kind of narrow opening that would have been closed with a wooden gate or barrier. Extending from the monument at the south-south-west is a trapezoidal enclosure measuring roughly 14 metres north to south, its shape and position suggesting it may have functioned as an annexe, possibly for penning animals. Roughly 230 metres to the west, another ringfort survives, which raises the possibility that this part of the landscape was once more densely settled than its current appearance suggests.