The structure rises four storeys high with walls measuring 1.7 metres thick and a diameter of 9.2 metres. Built from roughly coursed limestone rubble, the tower shows a distinctive base batter, though its eastern side has sadly collapsed over time. Inside, wooden floors once rested on stone corbels featuring punch dressing and drafted margins, whilst two ground floor gun loops and a first floor garderobe accessed via a mural passage in the southwest angle speak to its defensive purpose.

The tower reveals some intriguing architectural quirks; whilst the bottom two floors maintain a circular plan both inside and out, the upper two storeys shift to a square interior plan despite keeping their circular exterior walls. These upper levels remain largely obscured by ivy, making detailed examination challenging. Two fireplaces can be found on the southwest and northwest faces, their tall rectangular chimney stacks still protruding from the tower’s crown. Evidence of the original bawn wall remains visible, particularly where it attached to the southwest side of the tower before returning northeast. This defensive enclosure would have measured roughly 29.6 metres north to south by 24 metres east to west.

The castle grounds have seen considerable change since medieval times, with 19th century demesne walls now visible to the north and a Victorian house constructed to the southeast, built directly along the line of the original bawn wall. First recorded by Cooke in 1875, the site continues to offer insights into medieval defensive architecture and the power of the O’Carroll dynasty in this region of Ireland. The Archaeological Inventory of County Offaly, published in 1997, provides the foundational documentation for understanding this historic structure, though ongoing research continues to reveal new details about its construction and use.