This ancient circular enclosure measures 25.5 metres across its interior and is defined by a substantial earthen bank that still rises more than two metres high on its northern side. The earthwork features a low ledge running along the outer edge of the bank, beyond which lie the traces of what was once a water-filled defensive ditch, now silted up after centuries of disuse.

The fort's construction shows sophisticated defensive planning typical of early medieval Ireland. Along the eastern section, archaeologists have identified evidence of an internal stone revetment; essentially a stone facing that would have helped stabilise and strengthen the earthen rampart. A three-metre-wide gap in the southeast quadrant likely marks the original entrance, positioned to give the fort's inhabitants control over who could enter whilst maintaining clear sightlines across the surrounding landscape.

The choice of location reveals the strategic thinking of its builders. Positioned on good agricultural land with commanding views across the valley, this ringfort would have served as both a defendable homestead and a symbol of status in the landscape. These circular fortified farmsteads were the rural centres of Gaelic Ireland, typically housing extended families of some local importance along with their livestock, stores, and workshops. This particular example at An Tseanga Mheáin represents one of thousands of such sites that once dotted the Irish countryside, most dating from the early medieval period between roughly 500 and 1200 CE.