The Wessel Islands are a group of islands belonging to the Northern Territory of Australia. They extend in a more or less straight line from Buckingham Bay and the Napier Peninsula of Arnhem Land, and Elcho Island, to the northeast. Marchinbar Island is the largest of the group. Other islands include Elcho Island, Rimbija Island (the most outlying island), Guluwuru Island, Raragala Island, Stevens Island, Burgunngura Island, Djeergaree Island, Yargara Island, Drysdale Island, Jirrgari Island, Graham Island, Alger Island, Abbott Island, and Howard Island.
Bumaga Island and Warnawi Island, both part of the Wessel Islands group, are also part of the Cunningham Islands.
The islands were mapped and named by a Dutch expedition that sailed from Banda Neira to explore the coasts of New Guinea and the South Land following up on discoveries made in 1623 by Jan Carstensz and Willem van Colster (who named Arnhem Land after his ship Arnhem). The expedition used two small yachts that had been prefabricated in the Netherlands and were assembled on the Banda Islands, the Klein Amsterdam and the Klein Wesel (klein = small). The ships sailed on 17 April 1736 under the command of Gerrit Thomas Pool, who was killed on New Guinea just 11 days later. The merchant Pieter Pietersen took over command and continued the voyage, returning to Banda. Besides the Wesel Eilanden, named after the ship, Pietersen described the Cobourg Peninsula, Melville Island, and Dundas Strait. 170 years later Matthew Flinders decided to retain the name of the islands, though he slightly modified it to Wessel. The cities of Arnhem and Wesel, ultimate sources of the names of Arnhem Land and Wessel Islands, are themselves only 60 km (37 miles) separated.