Chûn Castle is a large Iron Age hillfort (ringfort) near Penzance in Cornwall, England, United Kingdom. The fort was built about 2,500 years ago, and fell into disuse until the 6th century AD when it was possibly re-occupied to protect the nearby tin mines. It stands beside a prehistoric trackway that was formerly known as the Old St Ives Road and the Tinners’ Way. The name Chûn derives from Cornish: Chi an Woon (‘the house on the downs’).