Follow the D781 out of Carnac. Proceed through Plouharnel. Drive past the first minor crossroads, and then turn left at the second crossroads that you encounter. Proceed down the Rue de Kerentrech Sainte-Barbe, watching out for the stones in a field to your left. Parking is available by the side of the road.
The Alignements de St Barbe is a collection of stones close to the Carnac monuments, arranged in a number of rows. Although it appears reasonably complete, many stones are believed to have been plundered for construction use in the nearby village. The remaining stones form three sides of a rectangle, with the shortest side consisting of the largest stones.
The Alignements de St Barbe are typical of the megalithic sites that seem to be liberally splattered across the countryside around Carnac. Forgotten and abandoned off the main tourist trail, this is a very impressive site with some extremely sizeable stones. The menhirs fronting the shorter side of the arrangement must be a good 12-15 feet in height. Very striking, and utterly unlike anything you'll see in Britain. The site gives the impression of a stone square! Highly recommended.