This massive flat-topped mound rises approximately 10 metres above its surrounding fosse, with a summit spanning 38 to 40 metres in diameter. The monument takes full advantage of the natural topography, positioned strategically at this confluence to maximise its defensive capabilities.

The mound is encircled by a deep fosse, roughly 3.5 metres wide at its base, with an substantial external bank that varies in height around its perimeter; 5.7 metres at the north, 3.3 metres at the east, and 1.2 metres at the south. Notably absent on the western side, the bank features gaps at both north and south, though these are likely modern additions rather than original features. The entire complex demonstrates sophisticated engineering typical of Anglo-Norman fortifications.

According to the twelfth-century chronicler Giraldus Cambrensis, this earthwork dates to his era, placing its construction during the early Anglo-Norman period in Ireland. The site has yielded some grim discoveries over the years; local antiquarian Price recorded finding skulls outside the northern section of the fosse and bank in 1966. Known locally as both 'Dinn Righ' and 'Ballyknockan moat', the monument was officially recognised for its historical significance in 1960 when it was entered into the Register of Historic Monuments.