Suomussalmi (Finnish: [ˈsuo̯muˌsːɑlmi]) is a municipality in Finland and is located in the Kainuu region about 90 kilometres (56 mi) northeast of Kajaani, the capital of Kainuu and 120 kilometres (75 mi) south of Kuusamo. The municipality has a population of 7,100
(31 August 2024) and covers an area of 5,857.60 square kilometres (2,261.63 sq mi) of which 587.03 km2 (226.65 sq mi) is water. The population density is 1.35 inhabitants per square kilometre (3.5/sq mi). The municipality is unilingually Finnish. Ämmänsaari is the biggest built-up area in the municipality.
Suomussalmi is the second southernmost part of the reindeer-herding area in Finland.