The Batu Islands are an archipelago of Indonesia located in the Indian Ocean, off the west coast of Sumatra, between Nias and Siberut. The three primary islands, of approximately equal size, are Pini, Tanahmasa, and Tanahbala. There are seventy-five smaller islands, of which the largest are Sipika, Simuk, Bodjo, Telo and Sigata; less than half are inhabited. The total land area of the seven administrative districts is 1,201.1 km2. The islands are governed as a part of South Nias regency within North Sumatra province. In Indonesian and Malay, batu means rock or stone.