Kemijoki is Finland’s longest river, flowing for about 550 kilometres from northern Lapland to the Gulf of Bothnia.
The river rises near the borders of Finland, Sweden, and Norway and runs through the city of Rovaniemi before reaching the Gulf of Bothnia at Kemi. Its drainage basin covers a large part of Finnish Lapland, and several tributaries, including the Ounasjoki, feed its main channel.
Kemijoki became central to Finland’s hydroelectric development during the twentieth century. Numerous power stations were built along the river, making it one of the country’s most important sources of hydropower. The largest plants are operated by Kemijoki Oy, a company established to manage hydroelectric production in the basin.
The river’s extensive dam system changed traditional migratory routes for salmon and other fish. This environmental issue is often part of discussions about restoring fish passage in northern Finnish rivers. Kemijoki should not be confused with Tornionjoki, which forms part of the Finland–Sweden border.