Mountpleasant House appears as an unlocated dwelling on the Down Survey maps dating from 1654 to 1657, one of the most comprehensive land surveys ever undertaken in Ireland. The Survey of Modern Records office has tentatively identified ruins marked on the 1838 Ordnance Survey 6-inch map as the possible location of this mysterious 17th-century residence, though the connection remains speculative.

Today, visitors to the site near Mountpleasant would struggle to find any trace of either structure. Where the 1838 map shows the ruins of Mountpleasant House, only a few weathered stones break through the grass, offering scant evidence of what once stood here. No architectural features or foundations dating to before 1700 have been discovered, leaving the exact location and nature of the original house shown on the Down Survey as an enduring mystery.

The site represents a common archaeological puzzle across Ireland, where centuries of abandonment, agricultural use, and natural decay have erased most traces of early modern domestic buildings. The Down Survey itself, commissioned by Oliver Cromwell to redistribute confiscated Irish lands to his soldiers and supporters, captured many such houses at a pivotal moment in Irish history; yet the physical remains of these dwellings have largely vanished, leaving researchers to piece together their stories from scattered documentary evidence and the faintest of archaeological traces.