The Kootenay River (spelled Kootenai River for its American portions) is the uppermost major tributary of the Columbia River, flowing through British Columbia, Montana and Idaho. It is the only river in North America which begins in Canada, enters the United States and then reenters Canada.

The Kootenay originates in the Rocky Mountains of eastern British Columbia, and initially flows south through Kootenay National Park, merging into the Rocky Mountain Trench near Canal Flats, British Columbia (here it passes within a kilometer of Columbia Lake , the headwaters of the Columbia). It continues southwards along the Trench towards the United States border, and at Wardner, British Columbia , it widens into the Lake Koocanusa reservoir created by the Libby Dam near Libby, Montana. Koocanausa spans the Canada-U.S. border; below the dam the river resumes (using the Kootenai spelling), veers westwards out of the Rocky Mountain Trench, crosses into Idaho, passes through Bonners Ferry, then turns northwards again. It re-enters Canada south of Creston, British Columbia, and widens into Kootenay Lake. At Nelson, British Columbia the Kootenay becomes a river again, now flowing southwest towards Castlegar, where it joins the Columbia.

See also

• Kootenai disambiguation page