LERINS, two small islands in the Mediterranean, off the coast of France, about 2½ miles from the shore at Cannes, and belonging to the department of Var. The larger one, called Ste Marguerite, is well wooded, and is defended by a fort which for many years was the prison of the mysterious "Man of the Iron Mask." The other islet, called St Honorat, contains the remains of a fortified convent. The former was the Leron, and the latter the Lesina of the Romans.