Frösön is the largest island in the lake Storsjön, located west of the city Östersund in Jämtland, Sweden. During most of recorded history the island was the regional centre of Jämtland. Frösön is the location of the "Frösö Runestone", the northernmost raised runestone in the world, dating from 1030-1050 AD. Frösön was a separate köping until 1974 but was merged with Östersund at that time.
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