Castle an Dinas is an Iron Age hillfort near St. Columb Major in Cornwall, UK and is considered one of the most important hillforts in the southwest of Britain. It dates from around the second to third century BCE and consists of three ditch and rampart concentric rings, 850 feet above sea level. During the early 1960s it was excavated by a team led by Dr. Bernard Wailes of the University of Pennsylvania.
The earliest written history was written by William of Worcester during his visit to Cornwall in 1478. He noted that legend says that the fort was the place where Gorlois, Duke of Cornwall and husband of King Arthur's mother, met his untimely death.
An extraordinary event that took place at the site was recorded by Cornish historian Samuel Drew, a ghost army was seen in the sky above Castle an Dinas around 1798. (If true, most likely an unusual but documented form of mirage.)
In 1904 a young woman was murdered on the site by a jealous lover, he too then took his own life...
The Old Cornwall Society hold their traditional annual midsummer bonfires here on the highest point of the fort.
From 1916 to 1957 it was the site of Cornwall's largest wolfram mine. Many of the old buildings and workings remain standing. The mine is the type locality for the mineral Russellite. Other minerals found here include: Arsenopyrite, Cacoxenite, Löllingite, Phlogopite, Russellite Topaz Turquoise