This rectangular stone structure, measuring roughly 13.65 metres east to west and 7.2 metres north to south, rises three storeys high with distinctive towers at its northeastern and southeastern corners. Built with thick walls and a barrel vault over the ground floor, the tower house exemplifies the defensive architecture common to medieval Ireland, though much of its original fabric has been altered or lost to time.

The building’s history took an interesting turn in 1512 when Sir Christopher Fleming and his wife, Elizabeth Stuckly, established a College of canons at Slane. They endowed it to support four priests, four clerks and four choristers, constructing a small cloister that connected directly to the existing tower house at its southeastern angle. This transformation from purely defensive structure to religious institution reflects the changing nature of Irish society in the early sixteenth century. Even after the College’s establishment, the tower house continued to serve as the parish priest’s residence well into the seventeenth century, with Archbishop James Usher noting in 1622 that it remained “a faire stone house or castle and offices reasonably repaired.”

The architectural details reveal much about medieval life within these walls. The original entrance, now destroyed, once stood at the western end of the south wall, elevated about a metre above ground level for defensive purposes. From here, a spiral staircase led to the first floor, whilst a separate newel stair at the northeastern corner provided the only original access between all levels. The ground floor features three double-splay windows in the south wall and one in the east, designed to admit light whilst maintaining security. Upper floors contained fireplaces, enlarged windows and garderobes built into the southeastern tower, though much of this tower’s masonry has since collapsed. A secondary passage was later cut through the north wall to connect with the College cloister, whilst corbels visible in the surviving walls once supported the timber second floor, showing how the building evolved to meet changing needs over its long history.