Kōriyama (郡山市, Kōriyama-shi) is a city in central Fukushima Prefecture, Japan. As of February 2015[update], the city has an estimated population of 329,339 and a population density of 435 persons per km². The total area was 757.06 km². Kōriyama is designated as a "core city" and functions as a commercial center for Fukushima Prefecture. Kōriyama is the second largest conurbation in the Tōhoku region.