Nagano Prefecture is a landlocked prefecture of Japan located in the Chūbu region of Honshū. Nagano Prefecture has a population of 2,007,682 and has a geographic area of 13,561.56 square kilometres (5,236.15 sq mi). Nagano Prefecture borders Niigata Prefecture to the north, Gunma Prefecture to the northeast, Saitama Prefecture to the east, Yamanashi Prefecture to the southeast, Shizuoka Prefecture and Aichi Prefecture to the south, and Gifu Prefecture and Toyama Prefecture to the west.

The Chūbu region , Central region, or Central Japan is a region in the middle of Honshū, Japan's main island. In a wide, classical definition, it encompasses nine prefectures (ken): Aichi, Fukui, Gifu, Ishikawa, Nagano, Niigata, Shizuoka, Toyama, and Yamanashi.