Lake Brienz (Brienzersee) is the eastern lake at the side of Interlaken at 564 metres above sea level. It is named after the village of Brienz which is found at its eastern end. It has a length of about 14 kilometres, and at its widest it has a width of 2.8 kilometres. Its maximum depth is 260 metres making it a significant body of water over its 29.8 square kilometres (11.5 sq mi), and the surface is 564 metres (1,850 ft) above the sea-level. It is fed by the upper reaches of the Aare at its eastern end 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 which in turn feeds into Lake Thun.
One can travel around it by vehicle, indeed the A8 motorway passes its southern shore (although it is not really a motorway - more of a toll road). However avoiding the motorway one can travel along the banks. The village of Iseltwald lies on the south shore although the best views are afforded by taking the northern shore which gives views of the mountains of the Bernese Oberland. Taking this route, one passes the villages of Ringgenberg, Niederried and Oberried The Brünig railway line also follows the northern shore of the lake.
Owing to a lack of nutritients in the lake, fish stocks are low. Nonetheless you can see small boats on the lake in the early morning in the accompanying photographs.
There have been passenger ships on the lake since 1839, and currently there are five passenger ships on the lake. The ships are operated by BLS AG, the local railway company, and link Interlaken Ost railway station, which they access using a 1.3-kilometre long navigable stretch of the Aare, with Brienz and other lakeside settlements. The ships also connect to the Giessbachbahn funicular, which climbs up to the Giessbach Falls.