Short answers, pulled from the story.
The name Sumatra derives from Haji Sumatrabhumi, a local king whose title meant "king of the land of Sumatra," who sent an envoy to China in 1017. Before that, Sanskrit-speaking traders called the island Svarnadwipa or Svarṇabhūmi, both meaning "Island of Gold" or "Land of Gold," referring to gold deposits in the highlands. Arab traders knew it as Ramni in the 9th century, then as Lamuri.
Sumatra covers 482,286.55 square kilometres, making it the sixth-largest island in the world and the largest island lying entirely within Indonesian territory. As of mid-2025, its population was estimated at about 62,259,500, with an average density of about 129 people per square kilometre.
Sumatra has lost almost 50 percent of its tropical rainforest since 1980, primarily due to deforestation linked to agricultural expansion and land clearing. Academics have described this destruction as an ecocide. The burning associated with deforestation caused the 2013 Southeast Asian haze, which created serious diplomatic tensions between Indonesia, Malaysia, and Singapore.
Five large mammals native to Sumatra are classified as critically endangered: the Sumatran tiger, Sumatran rhinoceros, Sumatran elephant, Sumatran orangutan, and Tapanuli orangutan. The Sumatran ground cuckoo has also reached critical endangered status. In October 2008, the Indonesian government announced a plan to protect Sumatra's remaining forests.
On the 26th of December 2004, an earthquake off Sumatra's western coast triggered a tsunami that killed more than 170,000 Indonesians, primarily in Aceh province. The earthquake itself lasted between 500 and 600 seconds, making it the longest earthquake ever recorded. Aceh province suffered the greatest destruction.
More than 52 languages are spoken in Sumatra. Nearly all of them belong to the Malayo-Polynesian branch of the Austronesian language family, with two sub-branches, Northwest Sumatra-Barrier Islands and Lampungic, found exclusively on the island. Indonesian, based on Riau Malay, serves as the official language and main lingua franca.