East Sumba Regency is geographically the largest of the four regencies which divide the island of Sumba, within East Nusa Tenggara Province of Indonesia. It occupies 62% of the entire island, being much less densely populated than the western third. The town of Waingapu is the capital of East Sumba Regency. The population of East Sumba Regency was …East Sumba Regency is geographically the largest of the four regencies which divide the island of Sumba, within East Nusa Tenggara Province of Indonesia. It occupies 62% of the entire island, being much less densely populated than the western third. The town of Waingapu is the capital of East Sumba Regency. The population of East Sumba Regency was 227,732 at the 2010 Census and 244,820 at the 2020 Census; the official estimate as at mid 2022 was 255,498.