This circular earthwork mound, measuring 25 metres across at its base and rising just 1.4 to 2.2 metres high, sits on level ground with a small valley running north to south about 20 metres to the east. The flat-topped summit spans 13 metres in diameter, whilst remnants of a defensive fosse, or ditch, can still be traced around the northern, southern and western sides, varying between 6 and 11 metres in width. Faint traces of an outer bank survive at the southeast corner, though these are barely 20 centimetres high.

The motte’s history likely dates to around 1200, when Hervey de Montmorency granted the churches of Shelburne and Bargy baronies to Christchurch Cathedral in Canterbury. The cathedral authorities subsequently granted the town of Fethard to Richard de Londres, with the specific condition that he construct a castle. Whilst this relatively low mound may have been that very castle, its modest height raises questions about whether it served as the primary fortification or perhaps formed part of a larger defensive complex.

The strategic placement of this earthwork becomes clearer when considering its neighbours; a church site lies approximately 40 metres to the south, whilst another castle structure stands just 25 metres to the southwest. This cluster of medieval sites suggests Grange was once a significant settlement during the Anglo-Norman period, with the motte serving as one element in a network of religious and military structures that helped establish and maintain Norman control over this part of County Wexford.