The Sarner Aa is a river located in the Canton of Obwalden in central Switzerland. It flows from the Sarnersee lake and travels approximately 12 kilometers before joining the Luzern river. The river is known for its picturesque surroundings, including lush forests and mountainous landscapes. The Sarner Aa is an important waterway for the region, providing both ecological benefits and recreational opportunities. It supports local wildlife and offers activities such as fishing and hiking along its banks. The river is also a popular spot for nature enthusiasts and tourists exploring the scenic beauty of the area.