The site consists of a circular earthwork, measuring 35 metres from north to south, enclosed by an earthen bank that stands two metres wide. The bank rises one metre high on the interior side and two metres on the exterior, with what appears to be the remains of a shallow outer ditch on the southern side. Whilst no obvious entrance has been identified, the defensive nature of these earthworks is clear.

The site’s history becomes more complex when considering the tower house built within its north-eastern sector. The south-eastern portion of the interior shows evidence of quarrying, likely carried out to provide building materials for the stone castle. This raises fascinating questions about the relationship between the two structures; the enclosing earthwork might represent an earlier ringfort, a type of fortified farmstead common in early medieval Ireland, which was later repurposed when the tower house was constructed.

Alternatively, the earthwork and tower house may be contemporary, with the bank and ditch serving as a bawn; a defensive enclosure that would have originally supported a timber palisade wall to protect the castle and its occupants. This dual interpretation reflects the layered nature of Irish archaeological sites, where centuries of occupation and adaptation have created complex historical narratives. The site at Bawn, Clonoghil Upper, serves as a tangible link to Offaly’s medieval past, whether as a reused ancient fortification or purpose-built castle defences.