This imposing earthen mound, also known locally as Rath Gorey moat, rises 7.3 metres high with a flat top measuring 10 metres across and a base spanning 30 metres in diameter. The structure is surrounded by a flat-bottomed fosse, or defensive ditch, and sits at the western edge of a crescent-shaped bailey that stretches 40 metres north to south. The bailey itself is defined by an earthen bank and external fosse, though parts of the northern section have been destroyed over time. Interestingly, the bailey may have been adapted from an earlier rath, a type of Irish ringfort, which would explain both its distinctive shape and its local name of Rathgorey.

The site likely served as the first administrative centre, or caput, of the manor of Rosegarland, a significant medieval holding that stretched between the Owenduff and Corock rivers, encompassing the parishes of Inch, Clongeen and Ballylannan. Maurice de London held the manor in 1247, controlling it through the service of two knights from the Vallence purpartry whilst also holding nearby Duncormick. The manor passed through various noble families over the centuries; by 1308 it had transferred through marriage to George le Poer, and in 1385 it passed to Simon de Neville. The Nevilles maintained control well into the 15th century, appearing in a feodary of 1425, and may have eventually relocated the manor’s centre from Newcastle to Rosegarland itself.

Archaeological monitoring in 2015 found no related material when a gas pipeline was installed about a metre east of the motte’s fosse, suggesting the immediate surrounding area saw limited medieval activity beyond the defensive structures themselves. Today, the overgrown mound remains a striking feature in the landscape, positioned on a slight rise at the eastern edge of fairly level ground with a small valley opening to the northeast. Its substantial earthworks speak to the strategic importance of this location in controlling and administering the surrounding territory during the tumultuous centuries following the Anglo-Norman invasion of Ireland.