Motomiya is a city located in north-central Fukushima Prefecture, Japan. As of 1 March 2020, the city had an estimated population of 30,401 i…Motomiya is a city located in north-central Fukushima Prefecture, Japan. As of 1 March 2020, the city had an estimated population of 30,401 in 10,680 households and a population density of 350 persons per km². The total area of the city was 88.02 square kilometres. It is the smallest city in Fukushima Prefecture, both in terms of population and size.