This rectangular tower house, measuring 14 metres east to west and 9.5 metres north to south, was once the stronghold of the Synan family until its forfeiture in 1639, when it was granted to St Leger. Today, visitors can still trace the sod-covered foundations of the bawn wall that once enclosed a roughly rectangular area extending east and south of the tower, creating a defensive courtyard approximately 45 by 40 metres.

The tower’s original entrance was through a ground-floor doorway on the eastern wall, now entirely missing, which led into a lobby area. From here, one could access the main ground-floor chamber straight ahead, a guard room to the north, or the foot of the mural stairs to the south. These stairs, though now broken, originally rose through the southeastern corner before continuing as a spiral to the wall-walk level. Each floor reveals fascinating defensive and domestic features; the first floor includes what may have been a murder hole above the entrance lobby, whilst the second and third floors contain garderobes and angle-loops for defence. The chambers throughout are lit by various window types, from simple slit windows to more elaborate ogee-headed lights set within vaulted embrasures.

The architectural details tell the story of late medieval Irish tower house design, with pointed and segmental vaults covering many of the chambers, and wicker-centred construction visible in several arches and vaults. The main third-floor chamber serves as an attic space beneath a bluntly pointed vault running east to west, whilst the second-floor chambers feature windows with square-set embrasures covered by segmental vaults. Though time and ivy have obscured some features, and the uppermost levels survive only as fragments, Castle Pook remains an impressive example of the fortified residences built by Anglo-Norman and Gaelicised families across Cork during the medieval period.