A kistvaen is a (usually pre-Christian) stone coffin, derived from the Celtic cist, meaning chest and maen meaning stone.

Many fine examples of kistvaens are to be found on Dartmoor. These often take the form of small rectangular pits about 3 ft. (0.9 m) long by 2 feet (0.6 m) wide. The kistvaens were usually covered with a mound of earth and surrounded by a circle of small stones. When a body was placed in the kistvaen, it was usually lain in a contracted position. Sometimes however the body was cremated with the ashes placed in a cinerary urn.