It is located in Innlandet and Trøndelag counties in Norway, just 13 km (8.1 mi) west of the border with Sweden.

Femundsmarka National Park borders the northeastern part of the lake.

But this was never officially recognised by the Dano-Norwegian government (since Norway was ruled from Copenhagen in the early modern age), and during border adjustments in 1751 the Femundsmarka area east of the lake was granted to Norway from Sweden.

The new (and current) border from 1751 is quite special: For a length of 61 kilometres (38 mi), it makes a completely straight line between the summits of the 1,002-metre (3,287 ft) tall mountain Våndsjögusten and the 1,185-metre (3,888 ft) tall mountain Østerhogna.

Straight-line national borders are very unusual in Scandinavia, except in the very northernmost parts.