Mt. Shirane is located on the border between Gumma and Tochigi prefecture.
Another Mt. Shirane is also in Kusatsu area. So Mt. Shirane in Nikko area is called Mt. Nikko-shirane and Mt. Shirane in Kusatsu area is called Mt. Kusatsu-shirane.
Mt. Nikko-shirane belongs to Nasu Volcanic Belt and the peak in Mt. Nikko-shirane is Mt. Oku-shirane which is highest in northern area from Kanto region.
You can see Cyuzenji-lake, Mt. Mae-shirane, Mt. Nantai, and big bogs like cobalt blue Goshikinuma, Suganuma, and Marunuma. The route through Mt. Oke-shirane and Mae-shirane is also popular. It takes 2.5 hours to reach to the summit if you use the gondola from Marunuma plateau.