Izunokuni is a city located in Shizuoka Prefecture, Japan. As of 10 July 2019, the city had an estimated population of 48,579 in 21,257 households and a population density of 506 persons per km2. The total area of the city is 94.62 square kilometres (36.53 sq mi).

Shizuoka Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. As of September 2023, Shizuoka Prefecture has a population of 3,555,818 and has a geographic area of 7,777.42 km2 (3,002.88 sq mi). Shizuoka Prefecture borders Kanagawa Prefecture to the east, Yamanashi Prefecture to the northeast, Nagano Prefecture to the north, and Aichi Prefecture to the west.