Batan is a dumbbell-shaped volcanic island, part of the Luzon Volcanic Arc. The northern part of the island is dominated by the high active volcano, Mount Iraya, which last erupted in 1454. The lower portion of the island is the inactive volcano Mount Matarem, about tall. A hilly narrow neck of land, about long and from wide, separates the two volcanoes of the island. Near Mt. Matarem, the island is at its widest at about .