This circular, dome-like mound measures roughly 60 metres in diameter and rises from a distinctive scarp that varies in height from half a metre to nearly one and a half metres along its southern arc. The mound is surrounded by an impressive berm, up to 7.5 metres wide and standing 1.75 metres high, which is itself enclosed by a combination of earthen and stone banks on the eastern side and scarps to the west and north.

The defensive features of this monument include a fosse, or defensive ditch, that runs intermittently around the structure, measuring between 6.5 and 8.3 metres wide and reaching depths of nearly a metre. The original entrance appears to have been on the northwest side, where a three-metre-wide causeway or ramp crosses the ditch. Whilst Bradley and colleagues initially classified it as a ringfort in 1985, the true nature of this fortification remains intriguingly ambiguous.

The most compelling theory suggests this may be the site of a castle built by Uilliam O’Farrell in 1405, rather than the motte and bailey located 770 metres to the northeast in Granard as traditionally believed. It could represent an earth and timber castle that was refortified during the 15th century, or perhaps more fascinatingly, it might be a rare example of a 15th-century Gaelic earth and timber castle; a distinctive Irish response to Anglo-Norman fortification techniques. Whatever its precise origins, this enigmatic earthwork stands as a testament to the complex military and cultural landscape of medieval Longford.