In 1792, Frenchman Joseph-Antoine Bruni d'Entrecasteaux, in charge of the ‘Recherche’ and ‘Esperance’(under Jean-Michel Huon de Kermadec), reached Cape Leeuwin on 5 December and explored eastward along the southern coast, anchored in Esperance Bay on 9 December.
While sheltering from weather off Observatory Island, the area was named Port Esperance (from d'Entrecasteaux’s ship), the name now given to the township and port. Recherche Archipelago, also known as the Bay of Isles is a group of 105 islands.