With a base diameter of 30 metres tapering to a 15-metre summit, this steep-sided fortification still bears traces of its defensive fosse, a shallow ditch that once encircled its northern, eastern and southern edges. The first Ordnance Survey map from 1838 reveals what appears to have been a bailey; a long, narrow rectangular enclosure extending northeast from the mound, suggesting this was once part of a more extensive motte-and-bailey castle complex typical of Anglo-Norman fortifications in Ireland.

Archaeological investigations carried out in 2002 ahead of golf course construction revealed fascinating evidence of medieval life around the castle. About 60 metres southwest of the motte, archaeologists discovered a substantial medieval ditch measuring 5.5 metres wide and 2.2 metres deep, which they traced for 50 metres as it ran northwest to southeast. This significant boundary feature was likely associated with the castle’s occupation, as was a medieval limekiln found during the same excavations. The disturbed remains of at least one medieval structure were uncovered just 35 to 40 metres from the motte’s edge, evidenced by compacted debris including crested ridge tiles, perforated roofing slates and decayed mortar, along with the remnants of two clay-bonded stone walls suggesting a building at least 12 by 3 metres in size.

The excavations yielded an impressive array of medieval artefacts: 280 pottery sherds, 175 roof tile fragments and 345 roofing slates, painting a picture of substantial medieval occupation at the site. More mysteriously, eight fragments of human skull from one adult and twelve additional skull fragments were recovered during monitoring, though their context remains unclear. The site continued to be occupied into the post-medieval period, with remains of farm buildings shown on 19th-century maps overlying the earlier medieval deposits, demonstrating how this strategic location by the Liffey has been continuously inhabited and adapted through the centuries.