The castle complex consists of a rectangular main block measuring 14 metres north to south and 11 metres east to west, with three projecting towers at strategic corners. The main tower is complemented by substantial bawn walls that form a defensive courtyard, with additional towers positioned at the southeast, northeast and northwest corners. During the Desmond rebellion of 1581, the castle was ‘defaced and despoiled’ and briefly fell into the hands of Sir Walter Raleigh, though David Barry managed to reclaim his ancestral home around 1583 and set about making substantial improvements to the structure.

The interior reveals a complex arrangement of chambers connected by narrow spiral staircases and mural passages. The main ground floor chamber features double-splayed windows, whilst the first floor boasts a barrel vault that replaced an earlier pointed vault, of which traces remain at the southern end. The second floor houses the principal chamber, an impressive space measuring approximately 12 by 6 metres, lit by elegant two and three light mullioned and transomed windows that were inserted into wide embrasures with built-in window seats. A particularly notable feature is the carved fireplace in the west wall, dated 1588, which partially blocked an earlier window embrasure during its installation. Throughout the tower, an intricate network of garderobe chambers, private quarters and even a chapel in the northeast tower speaks to the sophisticated living arrangements of a powerful medieval family.

Archaeological investigations carried out between 1992 and 2015 have revealed that the castle’s development spans several centuries. The projecting section of the north bawn wall, northwest tower and west bawn wall appear to be remnants of an early hall-type structure, possibly dating to the 13th or 14th century but largely rebuilt in the 15th century. The main tower house itself likely originated in the 15th century with a first floor entrance, though it underwent substantial rebuilding in the 16th century when the southwest corner tower was added and the current ground level entrance was inserted. Now a National Monument in State Ownership, Barryscourt Castle offers visitors a remarkable glimpse into the evolution of Irish castle architecture and the tumultuous history of medieval Cork, complete with 18th and 19th century farm buildings that were later incorporated into the bawn walls, including a former farmhouse that now serves as a coffee shop.