The Rumps Cliff Castle has three lines of ramparts built in the Iron Age, with the inner rampart being the earliest. The outer rampart is smaller from the other two. It has been proposed that this rampart may have been topped with a wooden palisade. The remains of round houses have been found between the middle and inner ramparts and in the interior. Past digs point to two main phases of occupation, beginning in the second century BC and continuing into the first century AD.
The Rumps cliff castle north from Rock along the coast to Pentire Point and Rumps Point and is reached by the coastal path or public footpath from Pentire Farm.