Nagano is the capital and largest city of Nagano Prefecture, located in the Nagano Basin in the central Chūbu region of Japan. Nagano is categorized as a core city of Japan. Nagano City is the highest prefectural capital in Japan, with an altitude of 371.4 meters (1,219 ft). The city is surrounded by mountains, the highest of which is Mount Takatsuma (2,353 m), and it is near the confluence of the Chikuma River—the longest and widest river in Japan—and the Sai River. As of 1 July 2023, the city had an estimated population of 365,296 in 160,625 households, and a population density of 438 persons per km². The total area of the city is 834.81 square kilometres (322.32 sq mi).

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.