Tintagel Castle is a medieval fortification located on the peninsula of Tintagel Island adjacent to the village of Tintagel (Trevena), North Cornwall in the United Kingdom. The site was possibly occupied in the Romano-British period, as an array of artefacts dating from this period have been found on the peninsula, but as yet no Roman-era structure has been proven to have existed there. It was settled during the early medieval period, when it was probably one of the seasonal residences of the regional king of Dumnonia. A castle was built on the site by Richard, 1st Earl of Cornwall in the 13th century, during the High Middle Ages. It later fell into disrepair and ruin.

Tintagel or Trevena is a civil parish and village situated on the Atlantic coast of Cornwall, England, United Kingdom. The village and nearby Tintagel Castle are associated with the legends surrounding King Arthur and in recent times have become a tourist attraction. It was claimed by Geoffrey of Monmouth that the castle was an ancient residence of King Arthur.