It has a long east-west extension but is relatively narrow in north-south direction, with a surface area of 24 km2 (9.3 sq mi).

On the south, the lake is overlooked by the Mürtschenstock Massif, whose peak is 2,441 m (8,009 ft) above sea level, and the resort area Flumserberg.

Quinten, located on the northern shore of the lake, can only be reached on foot from Weesen or Walenstadt via a hiking trail[3] or by boat (e.g. via a ferry from Murg) as there are no roads.

Unterterzen railway station is connected via a gondola lift with Oberterzen and the resort area Flumserberg.

[5] The lake provided the inspiration for a solo piano piece by Hungarian Romantic composer Franz Liszt, Au lac de Wallenstadt.