The castle is built on a small knoll and consists of a keep on the east side and a tower on the west, linked by walls to form a roughly circular enclosure. The building history is uncertain, but the keep is the oldest structure. It has been heightened twice, first by either Edward I or Maredudd ab Ieuan and second during the nineteenth-century restoration. The western tower may have been constructed in the late thirteenth century by Llywelyn ap Gruffudd or shortly after the English capture of the castle.