Tomasee

Lake Toma (Tomasee)
Lai da Tuma
Lake Toma (Tomasee) Show map of Canton of Graubünden Lake Toma (Tomasee) Show map of Canton of Uri Lake Toma (Tomasee) Show map of Switzerland Lake Toma (Tomasee) Show map of Alps
Location	Grisons
Coordinates	46°37′57″N 8°40′20″E / 46.63250°N 8.67222°E / 46.63250; 8.67222
Primary inflows	Rein da Tuma
Primary outflows	Rein da Tuma
Basin countries	Switzerland
Surface area	2.5 ha (6.2 acres)
Surface elevation	2,345 m (7,694 ft)

Lake Toma (German: Tomasee, Romansh: Lai da Tuma or Lag da Toma) is a lake at the northern face of Piz Badus, above the village of Tschamut in the canton of Grisons (Graubünden), Switzerland. Its surface area is 2.5 ha (6.2 acres).

It is the source of the Anterior Rhine and is deemed to be the official source of the Rhine (the source of the Posterior Rhine is above Hinterrhein, Switzerland, at 46°29′56″N 9°03′54″E / 46.499°N 9.065°E / 46.499; 9.065 (Source of Hinterrhein)).

It is possible to reach the lake on a path from Oberalp Pass, suitable for most walkers although still a mountain trail.^[1]