After a chapel was added to the property in 1844, modelled on the ruined monastery chapel of Ahamore Abbey on the nearby tidal Abbey Island, the house began to be called Derrynane Abbey, a designation that stuck despite the building having no monastic history whatsoever. It sits in woodland close to the northern shore of Derrynane Bay in County Kerry, a location that gives it a quality of mild seclusion, tucked away from the road and looking southward toward the sea.

The house is most closely associated with Daniel O'Connell, the nineteenth-century political leader credited with securing Catholic Emancipation in 1829. The oldest section of the building dated to 1702, though that portion was eventually demolished in 1967 during restoration work, having become structurally unsafe. What survives from O'Connell's own hand dates to 1825: the two-storey south wing that faces the water, and a crenellated library wing to the east. Crenellations, the battlemented parapets more commonly seen on medieval castles, were fashionable on domestic architecture of that period, lending a gothic or romanticised air to what was in practice a family home. By the time of O'Connell's death, the house had accumulated its unusual alias and its distinctive shape, part country house, part chapel, part mock-fortification. By 1964, however, the building had deteriorated badly enough that it was transferred to the Commissioners of Public Works. Restoration was completed in 1967 and the house was formally opened as a museum by President de Valera that same year. It now forms the centrepiece of Derrynane National Historic Park, which takes in some 300 acres of the surrounding land.