Its double banks and ditches, a ramp entrance and a causeway, and a central platform nearly 37 metres across suggest something more elaborate than the typical Irish ringfort, a circular enclosure of raised earth that was a common form of defended farmstead from the early medieval period. Specialists have noted that its morphology and deliberately engineered approach may point instead to a ringwork, a type of fortification with Norman associations, where the defensive architecture was designed as much to funnel and control movement as to simply enclose a space.

The fort escaped the attention of the first Ordnance Survey of 1839, and was still absent from a revision made in 1947, yet a detailed description, plan, and profile were published as early as 1850 to 1851 by a researcher named Dunne. He cut a deep north-to-south trench across the monument and retrieved human and animal bones, a rounded stone that he thought had been used to grind corn, and a fragment of bone from a knife or dagger handle. Dunne was struck by the defensive ingenuity of the site, writing that the approach wound around the steepest part of the bank and was commanded throughout by a platform set between the inner and outer ramparts. He connected the fort with a chief of the O'Broenains, a local Kilkenny dynasty. Writing in 1905, the historian William Carrigan added that the old name of the fort had been lost but might once have been Rathomin, or Toimin's Rath, a place mentioned repeatedly in documents relating to the O'Brenan family. The outer bank, inner bank, and two fosses, the latter being the ditches cut between the banks, survive in reasonable condition on most sides, though to the west they dissolve into a series of terraces cut directly into the hillside, a practical adaptation to the steep ground that drops away towards the valley floor. The whole monument is now heavily overgrown by trees, its contours softened but still legible beneath the plantation canopy.