The Dublin Gate in the south wall is a single round towered gate with an external barbican tower. It dates from the 1190s or early 13th century and was the first example of its type to be constructed in Ireland.

Apart from the keep, the main extant structures consist of the following: an early 14th-century three-towered fore work defending the keep entrance and including stables within it (accessed by a stone causeway crossing the partly filled-in ditch of the earlier ringwork); a huge late 13th-century