Lake Thun

Lake Thun is an Alpine lake in the Bernese Oberland in Switzerland named after the city of Thun, on its northern shore. At 48.3 km2 in surface area, it is the largest Swiss lake entirely within a single canton.

The lake was created after the last glacial period. After the 10th century, it split from Lake Brienz, before which the two lakes were combined, as Wendelsee. The culminating point of the lake's drainage basin is the Finsteraarhorn at 4,274 metres above sea level.Lake Thun's approximate 2,500 square kilometres catchment area frequently causes local flooding after heavy rainfalls. This occurs because the river Aare, which drains Lake Thun, has only limited capacity to handle the excess runoff. The lake is fed by water from Lake Brienz to the southeast, which is 6 metres higher than Lake Thun, and various streams in the Oberland, including the Kander.