The house that once stood here was a substantial affair, built on an H-plan, two storeys high with a dormered attic set into a steeply pitched roof, and a principal front where a five-bay centre was recessed between two projecting wings linked by a single-storey balustraded colonnade. It sat at the end of an avenue within a demesne that included a deer park, and its scale placed it firmly among the more ambitious country houses of its era in Leinster. By 1838, when the Ordnance Survey mapped the area at six inches to the mile, it was already recorded simply as "Downshire Ho. (in Ruins)".

The house was built by Michael Boyle, Archbishop of Armagh, in the late seventeenth century, and it was burnt in 1798, during the rebellion that convulsed much of Leinster that summer. The fire left the structure beyond recovery, and the demesne gradually absorbed what the flames had spared. Scattered across the surrounding landscape, and visible on aerial photographs, are features that may have belonged to the same designed estate: two circular ponds, one around forty metres in diameter and more than three metres deep with a path running around its lip; a smaller pond set within a subrectangular enclosure; and two circular mounds, each ringed by an external fosse, a shallow defensive or ornamental ditch. Whether these were formal garden features or served some more functional purpose is unclear, though their geometry suggests deliberate shaping rather than accident. Archaeological work carried out between 1998 and 2007, ahead of residential development on part of the site, confirmed that some field boundaries dated to the period of the house's occupation, and test trenches opened in 2003 recorded all surviving structural features. Topsoil stripping monitored through to 2007 also turned up three rubbish pits containing post-medieval artefacts, small material traces of a household that had otherwise largely vanished.