Rosepenna House, built around 1694 by Lord Boyne (Gustavus Hamilton), was originally an impressive H-plan residence with flanking towers crowned by conical roofs, formal terraced gardens, and marble piers that led visitors through embattled courts from the shoreline. The estate, situated in the townland of Magherilosky alias Rosapenna, represented the height of late 17th-century architectural fashion with its symmetrical design, tall sash windows, and carefully landscaped grounds complete with avenues, statues, and walled parks.

The house’s demise came dramatically during the fierce storms of 1785 to 1786, when shifting sands began to engulf the estate, burying parts of the building up to six metres deep. Despite the efforts of workmen to hold back the relentless dunes, the ground floor became uninhabitable whilst tenant John Dennison still occupied the property. The Reverend Mr Porter managed to live on the first floor until 1808, when the house was finally abandoned to nature. By 1827, visitor Rev. Caesar Otway found the entire estate; house, gardens, terraces, and parks; completely buried beneath a vast expanse of sand, with only the roof briefly visible before it too disappeared beneath the shifting landscape.

Today, careful observation reveals the ghostly footprint of this once-grand residence. The low wall footings trace the original H-plan layout, measuring approximately 23.8 metres by 8.2 metres, whilst remnants of the walled gardens can still be discerned to the north and south. Most remarkably, portions of the red brick walls from what appears to be an early 18th-century addition to the original structure survive up to 16 courses high in the central section, their narrow bricks bearing the distinctive lip marks of their original moulds. Some 90 metres northwest, a high mound marks where a gazebo or summer house once offered views across the estate, possibly built atop an earlier artificial mound, whilst an old roadway visible on Victorian maps can still be traced through the fields to the west.