The fort itself, roughly seventy metres square, had pointed bastions projecting from each corner, a form of defensive architecture designed to eliminate the blind spots that plagued older, straight-walled enclosures by allowing defenders to cover every angle of approach. Today the ditch, still four to four and a half metres wide and up to two metres deep, traces the outline of the structure well enough, though the vegetation has long since reclaimed everything above ground.

The fort was built in the 1650s under the direction of Orrery, almost certainly Roger Boyle, 1st Earl of Orrery, who was a significant figure in the Cromwellian and Restoration administration of Munster. It was re-fortified in 1672, a sign that it retained strategic value into the later seventeenth century, but it was demolished in 1689, a casualty of the upheavals surrounding the Williamite wars. Alongside the fort, and apparently contemporary with it, stood a settlement called Newtown, recorded with a population of 119 in 1659. That is a reasonably substantial community for the period and the location, which makes its disappearance shortly after all the more arresting. Local tradition places the village immediately to the north-east of the fort, but no visible remains have been identified above ground. Excavations carried out around 2000 and reported by C. Breen have investigated the site, though the settlement appears to have left little for the eye to find.