Today, not even its foundations remain visible; only historical records and old maps preserve its memory. The castle appears as a tower house on the 1654-7 Down Survey parish map, positioned west of Ballynamona Church, though it has often been confused with the nearby Ballynamona Beg Castle, which actually stood further south in what is now the townland of Castlefarm.

The castle's ownership tells a tale of changing fortunes in post-medieval Ireland. In 1583, James Foxe held the land, but the property changed hands frequently over the following decades, passing through J. Browne, Sir E. Fitton, N. Haward, and eventually to Edmund Baggott and D. O'Grady, who shared the castle between them in 1609, with O'Grady holding one third of the structure including the loft and half the cellar. By the time of the Civil Survey of 1654-56, the Rawly family; Edmund, Richard and Maurice; had taken possession of both Ballynamonamore and Ballincurra, though the survey notes the castle was already in decay, standing alongside ten cabins and a mill seat.

The physical destruction of Ballynamona More Castle was remarkably thorough. Writing in 1826, local historians noted the ruins were still visible near the west wall of the graveyard, but by 1840 the structure had been completely levelled. When antiquarian O'Kelly visited the site in 1943, he found it impossible to trace the castle's foundations, discovering only a single small angle of fallen masonry to mark where this once-prominent stronghold had stood. The castle's story serves as a reminder of how completely Ireland's medieval landscape has been transformed, with many such fortifications surviving only in placenames and archival documents.