Where the typical rath consists of a single earthen bank enclosing a roughly circular interior, this one layers defence upon defence: an inner bank, a fosse (a wide drainage or defensive ditch), a second bank, another fosse, and an outer bank beyond that. Three concentric barriers in a space barely thirty metres across. Whatever was being protected here, someone felt that one ring was not enough.

Ringforts were the most common form of enclosed settlement in early medieval Ireland, built and occupied roughly between the fifth and twelfth centuries. They functioned primarily as farmsteads, the banks and ditches serving less as military fortifications than as boundaries that kept livestock in and predators or opportunistic raiders out. The grading of a ringfort, from a simple univallate type with one bank to a multivallate example with three or more, is generally taken as a rough indicator of the status or wealth of whoever built it. By that measure, the Barroe fort sits towards the upper end of the scale. The inner bank runs between 3.55 and 8.05 metres wide, the second bank between 6.45 and 10.4 metres, and the whole arrangement is asymmetrical in places, with the second bank thickening noticeably on the south-south-western arc, its top widening to eight metres against the 3.8 metres found elsewhere on the circuit. The outer bank, meanwhile, is absent across the northern arc from north-north-west around to south, a gap that may reflect later disturbance or an original design choice.

The original entrance can still be read in the landscape: a narrow break of about 1.4 metres in the inner bank on the eastern side, with a slight causeway crossing the adjacent fosse and a corresponding gap in the second bank beyond it. The western and north-north-western perimeter is now densely overgrown and effectively inaccessible, so the eastern approach offers the clearest sense of the site's structure, even if the vegetation has long since softened the sharpness of the earthworks.