The "land of gold" is also the land of some great coffee. In ancient times that was the nickname given to this island because of a number of gold deposits discovered around the land.
Sumatra is a country with a long history, with travellers and settlers visiting from many countries throughout the centuries. But it wasn't until the late 1800s that coffee was first grown by Dutch colonists. Coffee had been introduced in Indonesian as far back as the 15th century, but not brought over to Sumatra until later. Most of the coffee grown on Sumatra is centered around Lake Toba in the Northern part of the island. Small farms sit on high plateaus that are rich in clay.
While Sumatra produces more coffee than any other Indonesian island, it also produces some very high quality coffee. O'Henry's sources green coffee from the Mandheling region. The region is to the north of Lake Toba and produces rich, earthly coffee that is slightly sweet and well balanced.
Another notable coffee from Sumatra is Kopi Luak. This infamous coffee goes for about $300/lb. Why? you ask? A small animal, called a luak, eats the bean digests it and so on. Villagers extract the bean from the animals excrement, clean it and prepare it for roasting. Taste profile is described as full-bodied and earthy.
Other growing regions in Sumatra include: Lintong and Aceh.