It is located in the province of Eastern Finland and is part of the North Karelia region.

The municipality has a population of 2,326 (31 December 2012)[2] and covers an area of 583.08 square kilometres (225.13 sq mi) of which 195.19 km2 (75.36 sq mi) is water.

The Swedish name is now considered outdated according to the Institute for the Languages of Finland.

[3] Kesälahti was first mentioned in 1589 as a part of the Uukuniemi parish (originally pogost).

In 1721 according to the Treaty of Nystad, which ended the Great Northern War, Uukuniemi was among the territories ceded to Russia (Old Finland), but Kesälahti was not included in the concessions.