Lamongan is a small stratovolcano in East Java located between the larger Tengger and Iyang-Argapura volcanoes. It is surrounded by numerous craters and cinder cones, forming a volcanic zone stretching 25 km E-W and 16 km N-S., and covering an area of 260 km2.
The volcano had many eruptions in the 19th century, but has probably not erupted since. It is remarkable and unusual for a subduction zone volcano for its many flank vents and relatively effusive eruption style. In the period of intense activity between 1799 and 1898, there were up to 15 basaltic lava flow eruptions.