Lake Brienz () is a lake just north of the Alps, in the canton of Berne in Switzerland. It has a length of about , a width of and a maximum depth of . Its area is , and the surface is above the sea-level. It is fed, among others, by the upper reaches of the Aare at its eastern end, the Giessbach at its southern shore from steep, forested and rocky hills of the high Faulhorn and Schwarzhoren more than above the lake, and by the Lütschine, flowing from the valleys of Grindelwald and Lauterbrunnen, at its south-western corner. It flows out into a further stretch of the Aare at its western end. The culminating point of the lake's drainage basin is the Finsteraarhorn at 4,274 metres above sea level.