|Location||St. Gallen, Glarus|
|Primary inflows||Linth (Escherkanal), Seez, Murgbach|
|Primary outflows||Linth canal|
|Surface area||24.19 km²|
|Average depth||104.7 m|
|Max. depth||151 m|
|Water volume||2.5 km³|
|Residence time||1.4258 years|
|Surface elevation||419 m|
|Settlements||Walenstadt, Weesen, Quinten, Quarten, Murg|
The Walensee is one of the larger lakes in Switzerland, for about 2/3 of its surface in the Canton of St. Gallen and for 1/3 in the Canton of Glarus. It is also known as Lake Walen or Lake Walenstadt, after Walenstadt. Other towns and villages at the lake include: Weesen, Quinten, Quarten, and Murg.
The three main rivers leading to this lake are the Seez, Murgbach, and Linth. The latter continues its course from Walensee to Lake Zurich. The Schnittlauchinsel, located at the eastern end of the lake, is the only island in the Walensee.
The Churfirsten range raises steeply on the north side from the lake's level at 419 m to 2,306 m above sea level. On the south, the lake is overlooked by the massif of the Mürtschenstock, culminating at 2,441 m. The highest point of the lake's drainage basin is the Tödi (3,614 m).
The lake provided the inspiration for a solo piano piece by Hungarian romantic composer Franz Liszt, called Au lac de Wallenstadt. The piece is part of a collection of solo piano works inspired by the composer's travels in 1830s Switzerland.