The rectangular tower, measuring roughly 5.25 metres north to south and 4.7 metres east to west internally, appears on the Down Survey barony map of Gowran from 1655-6, where it’s marked within Rathgarvan townland. Historical records from 1640 describe it as “a Castle in repaire” owned by James Blanchfield, though the family’s fortunes took a dramatic turn during the Cromwellian period when Richard Blanchville forfeited the property and was transplanted to Connaught with his wife and six children in 1654.

The tower house showcases typical defensive architecture of its era, built from roughly coursed limestone rubble with larger dressed blocks forming the corners. Its crenellated battlements remain intact, complete with a machicolation projecting from the southern end of the western wall; a defensive feature that allowed defenders to drop objects on attackers below. The original entrance sits at the northern end of the eastern wall, leading into a ground floor chamber that was once lit by narrow defensive loops. A mural staircase built into the thick northern wall connects the three floors, with the first floor featuring a pointed vault ceiling and the second floor later subdivided into three chambers by partition walls, though these modifications came much later than the castle’s original construction.

Despite centuries of weather and some relatively recent alterations, including the addition of brick window surrounds on the western wall, the castle retains many of its medieval features. The second floor preserves its fireplace with supporting mantle corbels in the eastern wall, whilst a narrow doorway at the eastern end of the southern wall leads to another mural staircase rising to the wall-walk where guards once patrolled. Evidence of an adjoining building can be seen on the northern face of the tower, and archaeological records note a possible 17th-century house situated nearby to the northeast, suggesting this was once part of a larger complex serving the Blanchfield family before their forced removal during the Commonwealth period.