Mount Mihara, Active volcano on Oshima Island, Japan

Mount Mihara is a basaltic central cone inside the caldera of Izu Ōshima, Tokyo. Its highest point, Mihara Shinzan, reaches 758 m, the island's highest summit. The cone rises about 150 m above the caldera floor, has a base diameter of roughly 1.2 km and holds a crater about 800 m wide, filled nearly flat by 1986 lava with a pit roughly 300 m across and 200 m deep toward the south.

The first record naming "Mihara" as an eruption site is a 1552 prayer plaque at a Yakushi hall in Motomachi. Major eruptions occurred in 1684–1690 and 1777, when lava overtopped the caldera wall and relief rice was granted. In 1950–51 lava buried the crater and formed Mihara Shinzan, now the island's highest point at 758 m.

Islanders have long called eruptions goshinka, the sacred fire, and the volcano itself Gojinka-sama, a fire deity to be revered. The name Mihara is traced to mihara, "belly" or womb, because the mountain discharges lava and debris flows as if giving birth. A shrine on the summit survived the 1986 eruption unharmed and is counted among Oshima's seven wonders.

The Obachi Meguri trail system leads hikers around the crater rim and offers several viewpoints overlooking the interior of the volcano. Guided tours help with orientation and provide information about current volcanic activity and safety guidelines.

The 1986 eruption sent lava fountains up to 1.6 km high and produced a 16 km subplinian plume, with a Volcanic Explosivity Index of 3. The summit shrine survived the eruption unharmed and is counted among the Seven Wonders of Oshima. The 1986 eruption also formed a rock known as Gojira Iwa, now a landmark.