Lungern is a municipality in the canton of Obwalden in Switzerland. It encompasses Lake Lungern and, besides the village of Lungern, the settlements of Bürglen, Kaiserstuhl and Obsee.

Lake Lungern is a natural lake in Obwalden, Switzerland which is named after the town Lungern on its shore. The lake is drained by the Sarner Aa river, which flows through the Sarnersee and into Lake Lucerne. The lake was originally much larger, and covered a large part of the valley it is situated in.