This is a rath, the most common type of early medieval settlement in Ireland, typically consisting of a raised earthen bank enclosing a circular or oval area where a farmstead once stood. Most were built between roughly the fifth and twelfth centuries, and Ireland has tens of thousands of them, yet each one marks a particular decision: someone chose this ground, on this slope, facing this direction, and built their home here.

The enclosure at Carrownadargny is oval in plan, measuring just over twenty metres by seventeen metres internally. Its bank, now softened by centuries of grass and erosion, still stands nearly a metre high on the interior and slightly more on the outer face, with a width of around four and a half metres. A southern entrance, about two and a half metres wide, would have been the threshold of daily life for whoever occupied the interior. That interior is described as uneven, which is often the case where the traces of structures, pits, or accumulated use have disturbed the ground beneath the sod. The western-facing slope on which it sits would have caught the afternoon light, though the steep gradient makes for an unusual setting; most ringforts favour more level ground.