Caer Drewyn is an early Iron Age hillfort to the north of the town of Corwen, Denbighshire (Grid reference SJ 08769 44411).
[1] Caer Drewyn is the most southerly hillfort in the Clwydian Range and Dee Valley Area of Outstanding Natural Beauty.
A later, larger fortress was surrounded by a dry-stone wall, probably derived from the abundant scree in the area, and does not have the earthen ramparts of other local hillforts.
[5] Caer Drewyn is an Iron Age fort dating back to about 500 BC, however it was in use as a defensive position long after this.
The Welsh antiquarian Edward Lhuyd mentioned Caer Drewyn in the late seventeenth century as "a place where they kept their cattle in war time".