The 'Tomaseemaarten' is a lake at the northern face of Piz Badus, above the village of Tschamut in Grisons, Switzerland. Its surface area is 2.5 ha.
It is the source of the Anterior Rhine and is deemed to be the official source of the Rhine.
It is possible to reach the lake on a path from Oberalp Pass, suitable for most walkers although still a mountain trail.
Wikipedia https://en.wikipedia.org/wiki/Tomasee
Address 7189, Switzerland
Coordinates 46°37'56.919" N 8°40'20.509" E
