Sundaland Sundaland is a biogeographical region of Southeastern Asia that comprises the Malay Peninsula and the Malay Archipelago islands of Sumatra, Java, Borneo, and surrounding smaller islands. The eastern boundary of Sundaland is the Wallace Line, identified by Alfred Russel Wallace, which marks the eastern boundary of the Asia's land mammal fauna, and is the boundary of the Indomalaya and Australasia ecozones. The islands east of the Wallace line are known as Wallacea, and are considered part of Australasia.