Nagano Prefecture (長野県, Nagano-ken; Japanese pronunciation: [naꜜɡano, naɡanoꜜkeɴ]) is a landlocked prefecture of Japan located in the Chūbu region of Honshu. It has a population of 2,007,682 as of 1 July 2023 and a geographic area of 13,561.56 square kilometres (5,236.15 sq mi). It 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.
Nagano is the prefecture's capital and largest city, with other major cities including Matsumoto, Ueda, and Iida. The prefecture is known for its impressive highland areas of the Japanese Alps, including most of the Hida Mountains, Kiso Mountains, and Akaishi Mountains, which extend into neighbouring prefectures; it contains nine of the twelve highest mountains in Japan. Its mountain ranges, natural scenery, and history have gained the prefecture international recognition as a winter sports tourist destination, and it received further attention as the host of the 1998 Winter Olympics. It is served by the Hokuriku Shinkansen railway line with direct services to Tokyo, Toyama, and Kanazawa.