The lands of Ballyness were originally granted to Henry Hart in 1611, who quickly sold them on to Wybrant Olphert, a Dutch Protestant settler. By 1619, records describe ‘a stone fort, and house in it’ occupied by an English family, though just three years later Olphert, then living in Derry, reported that he had repaired the ‘old bawn in some parts’, which otherwise ‘lyeth waste’.

Today, only fragments of this small rubble built bawn survive, with ivy covered walls offering glimpses of its former defensive strength. The north wall, standing up to 3.15 metres high despite having lost much of its lower facing, contains the original lintelled doorway complete with its draw bar hole and socket; essential security features for any frontier settlement. Behind this entrance lies an intriguing hall like feature with 2.5 metre high walls, accessed by stone steps built into the wall’s thickness. The doorway’s rear arch was once supported by a timber cross beam, and what might be the remains of a defensive loop can be seen west of the entrance.

The surviving sections include the northeast corner, fragments of the east wall with its slightly battered underpinning, and the lower courses of the south wall and southwest corner, though no trace remains of the western extent of the enclosure. Archaeological evidence suggests the north wall may have formed part of a house within the bawn, though no internal structures are now visible. Just north of the castle, the land has been scarped to accommodate two mill races, showing how this defensive site was later adapted for industrial purposes as the area became more settled and secure.