Iwamizawa is a city in Sorachi Subprefecture, Hokkaido, Japan. It is the capital of Sorachi Subprefecture. As of July 31, 2023, the city had an estimated population of 75,949 and the density of 158 persons per km2. The total area is 481.02 km2. On March 27, 2006, the town of Kurisawa, and the village of Kita merged into Iwamizawa.