Red cliff Castle is the remains of a later prehistoric cliff castle situated on a promontory north of Mawgan Porth. The castle is roughly crescent-shaped in plan, measuring up to 200 metres by 75 metres. The defences comprise two concentric ramparts, each with an external ditch, running north-south across the neck of the promontory.
From above you can make out the double ditch and banks that defended this headland from the mainland.
Presumably, when this was made, the headland was a lot bigger, as today it is pretty small, and would not have been worth all the effort to defend it to such an extent.