The monument at Rathacugga is a rath, an earthwork enclosure typically dating from the early medieval period, built by constructing one or more banks of earth and stone around a central living or farming area. What makes this particular example worth pausing over is its scale and its internal arrangement: at roughly 65 metres in diameter it is a substantial site, and it once contained an internal division that separated the south-eastern quadrant from the rest of the interior, an unusual feature suggesting a more complex use of space than the standard single-family farmstead model.

When Cody examined the site in 1989 and recorded it, the rath was already described as poorly preserved, defined by two banks with an intervening fosse, the ditch between the banks that would have added both drainage and a degree of defensive depth to the enclosure. A wide causewayed gap, some 15 metres across, opened at the southern side, the kind of formal entrance that would have allowed livestock and people to move in and out of the enclosed space. That record, imperfect as it already was, represents something now further lost. In 2011 the outer bank was levelled, and the displaced material was pushed inward to infill the fosse. The damage was not natural erosion or the slow attrition of centuries but a single episode of clearance that removed a substantial portion of what remained of the monument's original form.