What makes it worth pausing over is partly a matter of engineering: the northern portion of the interior has been deliberately raised some one and a half metres above the external ground level, a calculated response to the natural fall of the slope beneath it. Whoever built this wanted a level platform inside, and they moved enough earth and stone to get one.

The structure is a rath, the Irish term for a ringfort, the most common class of monument in the Irish countryside. Ringforts were typically enclosed farmsteads of the early medieval period, roughly the fifth to the twelfth centuries, in which a family and their livestock sheltered within a bank and ditch. This example in Culleeny Beg measures thirty-four metres in diameter across its enclosed space. Its bank varies considerably depending on where you measure it: the north-east to north section carries a bank about four and a half metres wide, standing roughly a metre above the interior and one and a half metres above the ground outside. A broader, lower bank runs along the north to north-east arc, wider at over eight metres but with far less height. The entrance, about two and a half metres across, faces north-north-west. A small depression in the western sector, around one and a half metres wide and forty centimetres deep, hints at something beneath the surface, though its purpose is not recorded.