A prehistoric passage grave built between around 4000 and 2500 BC, and in use until about 1000 BC. Excavations by F. C. Lukis began in 1840. The site is frequently mentioned in seventeenth century witch trials.
Inside the dolmen.
Close to the dolmen, the Mont Chinchon Battery, one of over sixty, was built as a defence against possible invasion by France. The cannons were cast between 1760 and 1820. It was also known as the Druids Altar Battery due to its closeness to the Trepied dolmen.