Island in Storsjön in Östersund Municipality, Sweden
Frösön (Swedish: [ˈfrø̂ːsˌøːn], Jämtlandic: [ˈfɾø̂ːsˌœʏːa]; "Frey's island"), (Old Norwegian: Frøys øy) is the largest island in the lake Storsjön, Jämtland, Sweden. Part of the city Östersund is located on the island. During most of recorded history Frösön was the regional centre of Jämtland, and it is the location of the Frösö Runestone, the northernmost in the world. The Swedish composer Wilhelm Peterson-Berger had a summer house (and from 1930 a permanent home) on the island.
https://en.wikipedia.org/wiki/Fr%C3%B6s%C3%B6n