Grand Barachois is a large natural lagoon in Saint Pierre and Miquelon. It lies immediately south of Miquelon Island, and is formed largely by the 12 kilometre-long tombolo of La Dune.
Coordinates: 46°59′20″N 56°19′20″W / 46.98889°N 56.32222°W / 46.98889; -56.32222