Sumba (Indonesian: Pulau Sumba) is an island in eastern Indonesia, is one of the Lesser Sunda Islands, and is in the province of East Nusa Tenggara. Sumba has an area of 11,153 km2, and the population was 656,259 at the 2010 Census. To the northwest of Sumba is Sumbawa, to the northeast, across the Sumba Strait (Selat Sumba), is Flores, to the east, across the Savu Sea, is Timor, and to the south, across part of the Indian Ocean, is Australia.
The largest town on the island is the main port of Waingapu, with a population of about 52,755. The landscape is low, limestone hills, rather than the steep volcanoes of many Indonesian islands. There is a dry season from May to November and a rainy season from December to April. The western side of the island is more fertile and more heavily populated than the east.