Iwakuni is a city located in Yamaguchi Prefecture, Japan. As of 1 June 2023, the city had an estimated population of 127,512 in 65182 households and a population density of 157 persons per km2. The total area of the city is 873.72 square kilometres (337.35 sq mi).

Yamaguchi Prefecture is a prefecture of Japan located in the Chūgoku region of Honshu. Yamaguchi Prefecture has a population of 1,377,631 and has a geographic area of 6,112 km2. Yamaguchi Prefecture borders Shimane Prefecture to the north and Hiroshima Prefecture to the northeast.