Bigourdan Fjord is a sound, 12 miles (19 km) long in an east-west direction and averaging 2 miles (3 km) wide, lying between Pourquoi Pas Island and the southwest part of Arrowsmith Peninsula, along the west coast of Graham Land. It was discovered by the French Antarctic Expedition, 1908–10, under Jean-Baptiste Charcot, and named by him for Guillaume Bigourdan, a noted French astronomer.