This earthwork, measuring roughly 29 metres north to south at its base and standing 1.67 metres high, features a flat top that would have once supported a timber castle structure. The mound is encircled by a substantial defensive fosse, a wide flat-bottomed ditch that varies between 4.3 and 6.2 metres in width, with an outer bank that adds another layer of fortification to this Norman stronghold.

The site’s history is intimately connected with the manor of Tullaghanbrogue and the Anglo-Norman settlement of Ossory. Historical records suggest that William de St. Leger held this manor, with his family maintaining their connection to the area until Cromwellian times. G.H. Orpen, writing in 1909, identified this earthwork as belonging to the ‘bretage’ type rather than a classic motte, suggesting it may have been among the last areas settled by the Anglo-Normans in central Ossory. The Down Survey maps from 1655-6 appear to show a ruined castle at this location, though no above-ground stonework remains visible today.

The mound sits within a rich archaeological landscape that tells the story of medieval settlement in this part of Ireland. Just 200 metres to the west stand the remains of the former medieval parish church of Tullaghanbrogue, whilst immediately to the east lie numerous earthworks including a small moated site and a large enclosure. A meandering stream once flowed to the north and west of the monument, visible on the 1839 Ordnance Survey map, though it has since been straightened. Today, brambles and hawthorn have colonised parts of the slopes, particularly on the north side and in the southeast sector where some quarrying has occurred, but the essential form of this Norman castle mound remains clearly visible, offering a tangible link to the medieval transformation of the Irish landscape.