To the west, the Ombai Strait separates Wetar from Alor Island, part of East Nusa Tenggara.

The islands of Wallacea have never been linked by land to either Asia or Australia, and as a result have few mammals and a mix of flora and fauna from both continents.

Romang and Damar are volcanic; Wetar consists mostly of oceanic crust that was pushed to the surface by the colliding plates.

Bugis and Makarassarese annually sailed to coral-rich Luang to purchase reef products such as trepang and mother of pearl.

[1] The Maluku Barat Daya Regency is administratively composed of seventeen districts (kecamatan), whose areas (in km2) and 2013 officially estimated populations are listed below.