What makes it worth pausing over is not its grandeur but its completeness of form: a subcircular rath, roughly 32 metres east to west and 30 metres north to south, defined by two concentric banks with a fosse between them. A fosse is simply a defensive ditch, and the double-bank arrangement here places this earthwork a modest step above the most basic single-bank ringforts that pepper the Irish countryside. Ringforts of this kind were the standard enclosed farmsteads of early medieval Ireland, built from roughly the fifth century through to the twelfth, and several thousand survive in various states across the island.

At Gortalough the inner bank has acquired a row of mature trees along its crest, which gives the enclosure an accidental dignity it was probably never intended to have. The outer bank is partially lost; it survives from the south-east around through the south and continues to the north-west, but the northern and north-eastern arc has been disturbed where a field boundary cuts across the fosse. That kind of intrusion is common in working farmland, where later generations rationalised boundaries without much concern for what lay beneath them. More intriguing is the entrance gap on the east-south-east side, which is formed as a causeway across the fosse rather than a simple break in the bank. Causewayed entrances of this type, where a raised crossing is left uncut through the ditch, are generally considered a sign of deliberate original construction rather than later damage, suggesting the gap has been in use since the rath was first occupied.