About fifteen metres into the pasture, sitting on a gentle north-facing slope, a roughly circular earthwork holds its shape with considerable composure. The bank, built from earth and stone, runs to eight metres wide and stands just over two metres high on its outer face, enclosing a space twenty-eight metres across. That gap between interior and exterior height is not accidental: the northern part of the interior floor has been deliberately raised by about 1.6 metres to level out the natural gradient of the hillside, a detail that speaks to real engineering forethought on the part of whoever built it.

This is a rath, the Irish term for a ringfort, the most common monument type surviving in the Irish landscape. These enclosures were typically built during the early medieval period, roughly between the fifth and twelfth centuries, and served as enclosed farmsteads for a single family or small community. The surrounding bank provided both a boundary marker and a degree of physical protection for the household and its livestock within. At Dromdiralough, the original entrance survives at the north-east, a two-metre-wide gap whose edges are reinforced with stone-facing on both sides. The inner face of the bank on the south to south-west also retains its stone-facing, suggesting that the structure was built with some care for permanence. A second breach in the bank at the south, also two metres wide, is likely a later disturbance rather than an original feature. The enclosure was already visible and legible enough to be mapped on the Ordnance Survey six-inch sheet of 1846, recorded there as a circular enclosure of approximately thirty metres in diameter, close to the figure measured on the ground today.