Iwaki is a city located in Fukushima Prefecture, Japan. As of 1 August 2023, Iwaki had a population of 322,019 in 143,500 households, and population density of 261 persons per km². The total area of the city is 1,232.02 square kilometres (475.69 sq mi), making it the largest city in the prefecture and the 10th largest city in Japan (2010) in terms of area. Iwaki is a designated core city, and is also one of the growing number of cities written in hiragana. The present Iwaki City started as the merger of 14 smaller municipalities on October 1, 1966. Every year, Iwaki hosts the Taira Tanabata Festival from 6–8 August.

Fukushima Prefecture is a prefecture of Japan located in the Tōhoku region of Honshu. Fukushima Prefecture has a population of 1,771,100 and has a geographic area of 13,783.90 square kilometres (5,321.99 sq mi). Fukushima Prefecture borders Miyagi Prefecture and Yamagata Prefecture to the north, Niigata Prefecture to the west, Gunma Prefecture to the southwest, and Tochigi Prefecture and Ibaraki Prefecture to the south.