Built during the reign of Henry VII (1485;1509) by Adam O’More, this fortification appears on both the Down Survey and the 1563 map of Laois and Offaly, marking its historical significance to the region. The castle’s strategic importance became evident during the 1534 rebellion when Silken Thomas and the Geraldines seized it as part of their uprising against English authority. Just over a decade later, in 1546, the Lord Justice arrived with the Earl of Desmond and their combined armies to reassert control over Laois, after which Ballyadams was granted to John Bowen, marking a shift in local power dynamics.

The castle complex consists of two distinct but connected structures that tell the story of changing architectural needs over centuries. At its heart stands the original tower house, to which a substantial three;storey limestone house was later attached on the eastern side. This rectangular addition, measuring 19.5 metres north to south and 11.42 metres east to west, showcases the evolution from purely defensive architecture to more comfortable residential accommodation that occurred during the seventeenth century. Built from roughly coursed limestone, the house features splayed window openings and rectangular windows along its north wall, whilst fireplaces in both the north and south walls provided warmth to its inhabitants.

What makes Ballyadams particularly intriguing is how these two buildings were integrated; access to the various floors of the later house could only be gained through the northwest tower of the original castle, creating an interconnected defensive residence. Archaeological evidence suggests the possible remains of a bawn wall at the southeast corner, which would have enclosed a courtyard area typical of Irish castle complexes. Whilst some portions of the house may actually date from the same period as the tower house itself, the majority of the structure clearly represents later modifications, illustrating how these fortifications adapted to changing times whilst maintaining their defensive capabilities.