Mt. Kusatsu-Shirane (2,160 m) is an active volcano in Kusatsu Town, Gunma Prefecture. Sometimes this mountain and its adjacent Mt. Ainomine and Mt. Moto-Shirane are generically called Mt. Kusatsu-Shirane. Mt. Kusatsu-Shirane is a popular scenic place with a variety of natural features such as bleak surface of mountains covered with volcanic ashes, forests of conifer trees and lakes surrounded with swamps.

The most attractive is the caldera lake called “Yugama” at the top of the mountain. The lake has a diameter of 300 m and a depth of 30 m. It contains beautiful emerald green water as if an artist had poured paint into it. The water in this lake is said to have the highest acidity in the world. There are also other caldera lakes of “Mizu-gama” and “Kare-gama” on both sides of Yugama.

In the area around Mt. Moto-Shirane, many hiking trails are provided and you can see a lot of alpine plants such as gentian, dicentra and alpine rose.