The village of Monktown, once comprising 162 acres of demesne land with a grand mansion house, belonged to St. Mary’s Cistercian abbey until the Dissolution of the Monasteries in 1540, when it was leased to Lady Eleanor Plunkett. Just 400 metres to the northeast, you’ll find the parish church, whilst the castle itself formed part of a larger estate that, by 1640, had grown to 295 acres under the ownership of Edward Dowdall and included not just the castle, but also a water mill and church.

What remains today is primarily the north wall of what was once a four-storey tower house, complete with well-preserved quoins. The original structure was rather sophisticated for its time, featuring projecting towers at the northeast and southwest corners; the southwest tower likely housed the staircase, though only the northeastern tower survives today. The main chamber boasts a north-south barrel vault over the ground floor, measuring approximately 4.6 metres east to west and over 4 metres north to south, with large windows punctuating the first and second floors and a smaller opening at the third level.

The surviving northeastern tower reveals fascinating architectural details, including what appears to be reused sandstone windows, suggesting materials were recycled from earlier structures. This tower could be accessed through lintelled doorways on each level, with wooden floors at the second and third storeys. Though the parapet has long since crumbled away, the corbelled roof of the third storey once supported a chamber at parapet level. Archaeological evidence suggests the castle may have been surrounded by a bawn measuring roughly 50 by 40 metres, with scarps still visible in the landscape, and a raised rectangular earthwork to the northwest possibly marking the location of former outbuildings.