Mount Rungwe is the center of the Rungwe Volcanic Province, a region of volcanic mountains that includes Mount Rungwe, Mount Ngozi in the Poroto Mountains and Kiejo. Rungwe Volcanic Province lies at a triple junction of rift valleys. The Lake Malawi Rift extends to the southeast, the Lake Rukwa rift to the northwest, and the Usungu Rift to the northeast. The region has been volcanically active from the late Miocene to historical times. Both Rungwe and Ngozi have had Plinian eruptions since the end of the Ice Age. The region has geothermal activity, including hot springs and warm springs. Rungwe is topped with a 4-km-wide caldera, breached to the WSW. Rungwe had a large explosive eruption about 4000 years ago, and the most recent eruption was about 1200 years ago. Kyejo last erupted around 1800.