Mount Tambora, also known as Tomboro, is situated in the northern part of Sumbawa island, part of the Lesser Sunda Islands. It is a segment of the Sunda Arc, a chain of volcanic islands that make up the southern chain of the Indonesian archipelago. Tambora forms its own peninsula on Sumbawa, known as the Sanggar peninsula. To the north of the peninsula is the Flores Sea and to the south is the long and wide Saleh Bay. At the mouth of Saleh Bay there is an islet called Mojo.