The Kander is a river in Switzerland. It is 44 kilometres (27 mi) long and has a watershed of 1,126 square kilometres (435 sq mi). Originally a tributary of the Aar river, with a confluence downstream of the city of Thun, since 1714 it has flowed into Lake Thun upstream of the city. The valley through which the river flows is known as the Kandertal or, in specific sections, as the Gastertal or Frutigtal.