Hyrynsalmi is a municipality in Finland and is part of the Kainuu region. The municipality has a population of 2,063 and covers an area of 1,521.38 square kilometres of which 100.32 km2 is water. The population density is 1.45 inhabitants per square kilometre. The municipality is unilingually Finnish. The world championships in swamp football is held annually in Hyrynsalmi.