Final answer:
The Klarälven river is located in Sweden and empties into Lake Vänern, the largest lake in Sweden.
Step-by-step explanation:
The country that has the Klarälven river, which empties into Lake Vänern, is Sweden. Lake Vänern is the largest lake in Sweden and the third-largest lake in Europe. The Klarälven flows through the provinces of Värmland and Dalarna before reaching Lake Vänern, contributing significantly to the lake's water volume. This geographical feature is a notable part of the Swedish landscape, impacting local ecosystems and being a point of interest for environmental studies.