Islands
Japan is composed of thousands of islands. The four largest main islands are Hokkaido, Honshu, Shikoku, and Kyushu. These islands are the peaks of mostly submerged mountains.
Mountains
More than 75 percent of Japan's land surface is covered in mountains, some with peaks over 9,800 feet. The Hida and the Akaishi are the two main mountain ranges. Both run north to south on Japan's largest island, Honshu.
Volcanoes
Japan has 20 active volcanoes as of 2009. There are 245 more dormant volcanoes, the tallest and most famous being Mount Fuji at 12,388 feet.
Plains
Roughly 29 percent of Japan is covered in plains, most located along the seacoast. The Kanto Plain is the largest, located in central Honshu and spanning about 6,500 square miles.
Lakes and Rivers
Japan holds many streams, but its rivers tend to be short. The longest river is the Shinano, located in Honshu, at 228 miles. The largest lake is Lake Biwa, located in west-central Honshu, at 259 square miles.