This impressive motte stands five metres high, with a broad base spanning 26 metres that tapers to a 14-metre-wide flat summit. Built around 1200 AD, the mound represents one of the early Anglo-Norman fortifications that once dotted the Irish landscape, marking the territorial ambitions of medieval lords who sought to control strategic locations across the country.

The Newcastle motte appears to have been constructed as a standalone defensive structure, with no surviving evidence of an accompanying bailey that typically formed part of these motte-and-bailey castles. Historical records add an intriguing dimension to the site; Austin Cooper, writing in 1780, documented the presence of a very deep and wide fosse, or defensive ditch, surrounding the mound. This substantial earthwork has since vanished from the landscape, leaving only Cooper’s account as testimony to its former existence.

Today, the motte remains a prominent feature in Newcastle’s rural setting, its grassy slopes offering a tangible connection to the area’s Anglo-Norman past. The structure would have originally supported a wooden tower or palisade on its summit, providing both a defensive stronghold and a visible symbol of Norman authority. Though the timber structures have long since disappeared, the earthen mound endures as a monument to the medieval transformation of the Irish landscape, when new fortification techniques arrived with foreign settlers and reshaped both the physical and political geography of Dublin’s hinterland.