Elcho Island, also called Galiwinku or Galiwin’ku, island, Northern Territory, Australia, in the Arafura Sea. It is situated 2 miles (3 km) across Cadell Strait from the Napier Peninsula and is a part of Arnhem Land, a large region belonging to the Yolngu Aboriginal people. The low-lying island is 30 miles (48 km) long by 7 miles (11 km) wide and is separated from the Wessel Islands (east) by Brown Strait.