The municipalities represent the local level of administration in Finland and act as the fundamental, self-governing administrative units of the country. The entire country is incorporated into municipalities and legally, all municipalities are equal, although certain municipalities are called cities or towns. Municipalities have the right to levy a flat percentual income tax, which is between 16 and 22 percent, and they provide two thirds of public services. Municipalities control many community services, such as schools, health care and the water supply, and local streets. They do not maintain highways, set laws or keep police forces, which are responsibilities of the central government.

Sottunga is an island municipality of Åland, an autonomous territory of Finland. The municipality is the smallest when it comes to population in Åland and in Finland, with a population of only 115 (31 December 2023) and covers an area of 342.44 square kilometres (132.22 sq mi) of which 314.41 km2 (121.39 sq mi) is water. The population density is 4.1 inhabitants per square kilometre (11/sq mi). The municipality is unilingually Swedish, with 93% of the inhabitants speaking Swedish as their native language. Sottunga comprises many islands, of which only three, Husö, Finnö and Storsottunga, are inhabited. Storsottunga is usually called Sottunga. There are five villages in the municipality: Finnö, Husö, Hästö, Mosshaga and Sottunga. The highest point of Sottunga is Kasberget.