Nias (nēˈäs) [key], volcanic island (1990 pop. 588,543), 1,842 sq mi (4,771 sq km), Indonesia, in the Indian Ocean, off Sumatra. Most of the population are descended from the Niah people; their economy is largely agricultural. The chief town is Gunungsitoli. Native handicraft is highly developed; megalithic shrines dot the land. The Dutch began trading there in 1669. The island is subject to severe earthquakes, that of Mar., 2005, being the most recent and especially devastating, killing more than 700 there and on neighboring islands.