Iwanuma (岩沼市 Iwanuma-shi?) is a city located in Miyagi Prefecture, in the Tohoku region of northern Japan. As of September 2015, the city had an estimated population of 44,149 and a population density of 730 persons per km². The total area was 60.71 square kilometres (23.44 sq mi). Iwanuma is at the convergence of two ancient roads, the Tōkaidō (via the Pacific coast) and the Tōsandō (inland route), both originating in the Kansai region.