| Mount Iō | |
| Other Name: | 硫黄岳 |
| Elevation M: | 703.7 |
| Elevation Ref: | [1] |
| Listing: | List of mountains and hills of Japan by height |
| Translation: | Sulphur Mountain |
| Language: | Japanese |
| Location: | Iōjima, Kagoshima Prefecture, Japan |
| Range: | Kikai Caldera |
| Coordinates: | 30.7931°N 130.3053°W |
| Topo: | Geographical Survey Institute, 25000:1 薩摩硫黄島, 50000:1 開聞岳 |
| Type: | Stratovolcano |
| Age: | Holocene |
| Volcanic Arc/Belt: | Ryukyu arc |
| Last Eruption: | June 2013 |
also Mount Iwo is an active rhyolitic lava dome on Iōjima in Kagoshima Prefecture, Japan. It sits within the borders of the town of Mishima.
The mountain is made up of non-alkali felsic rock and pyroclasitic flows.[2]