Nihonmatsu is a city in Fukushima Prefecture, Japan. As of 1 April 2020, the city has an estimated population of 54,013 in 20,179 households, and a population density of 160 persons per km2. The total area of the city was 344.42 square kilometres. The Adachi neighborhood of Nihonmatsu was the birthplace of artist Chieko Takamura, subject of the book of poems Chieko's Sky, written by her husband Kōtarō Takamura.