Mount Unzen is located in Kyushu, Japan. Here is a map to help you locate it. Use the plus and minus keys to see its location in relation the rest of the world. It is the most densly populated island in Japan so when Mount Unzen erupts it is very dangerous because so many people live around the volcano. The population is approximantly 13,064,955 with only 13,760 miles of land space so it is densly populated so the eruption of the volcano would kill a lot of people.