It is the tenth-largest lake in Norway with a surface area of 79.1 square kilometres (30.5 sq mi) and a volume of 1,573,523,000 cubic metres (1,275,676 acre⋅ft).

Møsvatn is Norway's fourth largest hydroelectric power reservoir with an energy content corresponding to approximately 2,300 gigawatt-hours (8,300 TJ).

There are several small, isolated farm communities located along the borders of the lake, most of which do not have road connections, so the main mode of transportation is by boat.

[2] On 19 November 1942, as part of the efforts to sabotage German heavy water production, glider-borne troops were to land on the frozen lake Møsvatn near the Vemork hydroelectric plant, run by Norsk Hydro, near the town of Rjukan.

This effort was not successful; however ultimately the Norwegians stopped the heavy water production activities and helped limit the German nuclear weapons research program.