Mattmark dam is a reservoir in the Saas Valley of the Canton of Valais, Switzerland. The Mattmark dam was built from 1960–1965. The lake's surface area is 1.76 km2.
The lake lies at a height of 2,197 metres above sea level, between the massifs of the Rimpfischhorn and Stellihorn. The highest peak visible from the lake is the Strahlhorn.
Wikipedia https://en.wikipedia.org/wiki/Mattmarksee
Address 3906, Switzerland
Coordinates 46°2'16.139" N 7°57'38.545" E
