The largest lake in the valley is lake Oeschinen. It is located at 1,578 m (5,177 ft) east of Kandersteg, at the foot of the Blüemlisalp massif. The Gastern Valley is an almost closed off valley. At the upper end of the valley lies the Kander Glacier, the source of the 44 km (27 mi) long Kander river. The Gastern Valley is on the way to the 2,700 m [8,900 ft] high Lötschen Pass.Part of the municipality is located within the Jungrau-Aletsch area, declared a UNESCO World Heritage Site in 2001 and extended in 2007. The area comprises Lake Oeschinen and the Gastern Valley.