Yanaizu is a town located in Fukushima Prefecture, Japan. As of 1 November 2019, the town had an estimated population of 3,304 in 1,269 households, and a population density of 19 persons per km². The total area of the town was 175.82 square kilometres (67.88 sq mi).

Fukushima Prefecture is a prefecture of Japan located in the Tōhoku region of Honshu. Fukushima Prefecture has a population of 1,771,100 and has a geographic area of 13,783.90 square kilometres (5,321.99 sq mi). Fukushima Prefecture borders Miyagi Prefecture and Yamagata Prefecture to the north, Niigata Prefecture to the west, Gunma Prefecture to the southwest, and Tochigi Prefecture and Ibaraki Prefecture to the south.