Storsjön (, lit. "The Great Lake") is the fifth largest
lake in
Sweden, with an area of 464 km² and a greatest depth of 74 m. It is located in the province of
Jämtland in modern
Jämtland County. From Storsjön runs the river
Indalsälven and the lake contains the major island
Frösön. The city of
Östersund is located on the east shore of the lake, opposite Frösön.