Iwaki is a city located in Fukushima Prefecture, Japan. As of 1 April 2020, Iwaki had a population of 337,765 in 143,500 households, and population density of 270 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. 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.