The Alas Strait is a strait that separates Lombok and Sumbawa, two islands of Indonesia in West Nusa Tenggara province.
The strait was bridged by land until about 14,000 years before present when sea level rose to about 75 meters below present sea level,unlike Lombok Strait and Alor Strait which continued to be water gaps even during the Last Glacial Maximum, at each end of a 400-mile-long island including present-day Lombok, Sumbawa, Komodo, Flores, Solor, Adonara, and Lembata.
Lombok is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is roughly circular, with a "tail" (Sekotong Peninsula) to the southwest, about 70 kilometres (43 miles) across and a total area of about 4,566.54 square kilometres (1,763.15 square miles) including smaller offshore islands. The provincial capital and largest city on the island is Mataram.
Lombok is somewhat similar in size and density, and shares some cultural heritage with the neighboring island of Bali to the west. However, it is administratively part of West Nusa Tenggara, along with the larger but less densely populated island of Sumbawa to the east. Lombok is surrounded by a number of smaller islands locally called Gili.