Mount Sindoro, Mount Sindara or Mount Sundoro is a semi-active stratovolcano in Central Java, Indonesia. Parasitic craters and volcanic cones are found in the northwest-southern flanks; the largest is called Kembang. A small lava dome occupies the volcano's summit. Historical eruptions have been mostly mild to moderate. The Sindoro mountain complex serves as the headwaters for the Progo river basin on the eastern slope and the Serayu river basin on the western slope.