Lieksa (Finnish pronunciation: [ˈlie̯ksɑ]) is a town and municipality of Finland.

[1] The population density is 2.94 inhabitants per square kilometre (7.6/sq mi).

Neighbouring municipalities are Ilomantsi, Joensuu, Juuka, Kontiolahti, Kuhmo and Nurmes.

Lieksa has more continental characteristics than most of the Nordics and Finland, making it prone to extreme temperatures, especially in winter.

On a typical winter night, the temperature drops to around −15.0 °C (5.0 °F) and readings as low as −30.0 °C (−22.0 °F) are not unusual.