Iwakuni (岩国市, Iwakuni-shi) is a city located in Yamaguchi Prefecture, Japan.
Iwakuni was formerly the castle town of the Iwakuni han, which was formed by Lord Hiroie Kikkawa after he was banished there for supporting the defeated shogun. The Kikkawa clan ruled the han during the Edo period. The han was originally assessed at 30 thousand koku, and later, 60 thousand. Iwakuni han prospered for 300 years up until the Meiji Restoration. Before being re-founded with the same name following the mergers in 2006, the city was first founded on April 1, 1940.
On March 20, 2006, Iwakuni absorbed the towns of Kuga, Mikawa, Miwa, Nishiki, Shūtō and Yū, and the village of Hongō (all from Kuga District) to create the new and expanded city of Iwakuni.
Located at 34° N, 132° E, Iwakuni is in the eastern part of Yamaguchi Prefecture, bordering the Seto Inland Sea.
As of January 2012, the city has an estimated population of 104,004 (which the city has decreased in population by 50,000 over the last 25 years) and a population density of 119.02 of persons per km². The total area is 873.78 km².