Lamarck Island is a rocky island 250 m long, lying 300 m east of Petrel Island and 300 m north-east of Rostand Island in the Géologie Archipelago, off the Adélie Coast of Antarctica. It was charted in 1951 by the French Antarctic Expedition and named by them after Jean-Baptiste Lamarck, the French naturalist.
The island is south of France.