That appears to be what happened somewhere along the Malahide Road in north County Dublin, where an earlier Donnycarney House once stood, quite separately from the eighteenth-century structure that would later carry the same name. The original building is unlocated, its footprint unknown, its fabric entirely vanished from the record.

What survives is a single firm detail: in 1649, the house was the residence of William Basil, who held the office of Attorney General. According to Wren's 1983 account of the area, this earlier house lay on the opposite side of the Malahide Road from the later Donnycarney House, placing it within what are now the grounds of Marino, the northside Dublin suburb best known today for the Casino, a neoclassical pleasure house built for James Caulfeild, Earl of Charlemont, in the 1760s. The irony is considerable: one of the most precisely studied small buildings in Irish architectural history now occupies land that may once have held a house whose very outline cannot be determined. When the eighteenth-century Donnycarney House was built, the name migrated across the road with it, and the earlier structure slipped out of the documentary record almost entirely.

There is, practically speaking, nothing to visit. The grounds of Marino are accessible to the public, and the Casino itself is managed by the Office of Public Works, but no physical trace of the earlier house has been identified. The site compiled by Geraldine Stout and uploaded to the record in September 2011 carries the frank admission that the exact location is unknown. For anyone interested in the layered history of this part of Dublin, the absence is itself worth noting: a house associated with a significant legal officer during a turbulent period in Irish history, gone so completely that even its general position within a suburban neighbourhood can only be approximated from a road reference and a landowner's name.