Torneälv (tōrˈnəĕlv) [key], Finnish Torniojoki, river, c.320 mi (510 km) long, rising in N Sweden at the Norwegian border. The river, which drains Torneträsk lake (126 sq mi/326 sq km), flows SW into the Gulf of Bothnia. It receives the Lainioälv at Anttis and forms the Swedish-Finnish frontier below its junction with the Muonioälv (Finnish Muoniojoki ), its chief tributary. The Muonioälv forms the Swedish-Finnish frontier from its source at the Norwegian border to its confluence with the Torneälv. The Torneälv has several falls and is rich in salmon. Haparanda (Sweden) and Tornio (Finland) are located at its mouth.