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 early centuries 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 area is now sometimes known as Chûn Downs. Nearby is Chûn Quoit.

The Cornwall Wildlife Trust is a charitable organisation founded in 1962 that is concerned solely with Cornwall, England, United Kingdom.