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, making it the largest city in the prefecture and the 10th largest city in Japan in terms of area. Iwaki is a designated core city, and is also one of the growing number of cities written in hiragana.