The site comprises a substantial defensive system with two fosses or moats, each measuring between 2.2 and 4 metres wide and up to 1.8 metres deep, separated by an impressive flat-topped bank that rises over 3 metres high with a base spanning roughly 9 metres. Though the southeast side has been lost to a modern farmyard, the remaining three sides of this 28 by 44 metre enclosure remain intact, albeit overgrown, and currently serve the rather humble purpose of a haggard with a farm building at its centre.

The land here has deep Norman roots stretching back to the late 12th century when William Brun and his son Nicholas witnessed Hervey de Montmorency’s charter to Dunbrody Abbey sometime between 1178 and 1182. The Brun family maintained their hold on Mulrankin for generations, holding it as half a knight’s fee from the powerful Bigod estate; William in 1247 and Nicholas in 1307, though their original stronghold was likely the motte at nearby Oldhall. By the late medieval period, the Browns (as the name evolved) had established themselves at Ballycappoge, with Patrick Browne recorded in 1381 managing 160 acres here alongside the now-lost townland of Drumfellin.

The site’s transformation from medieval stronghold to agricultural use reflects broader patterns of Irish history. By 1640, according to the Civil Survey conducted in the 1650s, David Brown held both castle and 180 acres at Ballycappoge, though by then Drumfellin had vanished from the records, likely absorbed into the larger estate. While the 1940 Ordnance Survey map marks a castle within the moated site, the earthworks themselves probably constituted the defensive structure, a typical arrangement for lesser Anglo-Norman holdings. Recent archaeological testing about 100 metres southeast of the site in 2006 yielded no finds, suggesting the medieval activity remained concentrated within the moated enclosure itself.