Aursunden[2] is a lake in Røros Municipality in Trøndelag county, Norway.

The outflow is regulated by a hydropower dam through which water passes into the river Glomma.

The deepest part of the lake reaches a depth of 52 metres (171 ft).

The actual headwaters are near Aursunden near the start of the Glommadal valley.

The locals claim that the headwater of the Glomma river is Mustjønna, a tiny lake about 30 kilometres (19 mi) north of Aursunden.