This impressive fortification at Kilnahone consists of a raised circular interior space, roughly 21 to 26 metres across, surrounded by formidable defensive earthworks. The monument’s overall footprint stretches approximately 100 metres north to south, making it a substantial presence on the landscape.

What makes this site particularly remarkable is the unusual preservation of its defensive features. The enclosure is protected by three distinct elements: an inner bank of earth and stone standing up to 4.5 metres high in places, a wide flat-bottomed fosse (defensive ditch) that remains waterlogged on its southern side, and an outer bank that completes the defensive circuit. The profiles of these earthworks are so well preserved that they appear almost original, though they may have been recut during the post-medieval period. The inner bank’s external face and the outer bank’s internal face are actually vertical in some sections, while the gradual slope from the inner bank down into the interior creates an amphitheatre-like effect similar to the famous Beal Boru in County Clare.

Access to the interior was controlled through a single causewayed entrance, 3.5 metres wide, on the southwestern side. Today, the entire monument is heavily overgrown with dense thorn bushes that make detailed examination of the perimeter nearly impossible, though evidence of hazel coppicing can be seen around the enclosure’s edges. Despite some damage to the banks on the southern side, this hilltop fortification remains one of the most impressive examples of its type, clearly representing a high-status or heavily fortified site that once played an important role in controlling and surveying the surrounding territory.