Carnac is a commune beside the Gulf of Morbihan on the south coast of Brittany in the Morbihan department in north-western France.

The Morbihan is a department in the administrative region of Brittany, situated in the northwest of France. It is named after the Morbihan, the enclosed sea that is the principal feature of the coastline. It had a population of 759,684 in 2019. It is noted for its Carnac stones, which predate and are more extensive than the Stonehenge monument in Wiltshire, England.