The original Zwijnsbergen Castle was a fortified manor in the Middle ages. The oldest parts of the current castle were built in the mid-1400s. The tower dates from around 1552. The current main building was erected in the 17th century and restored in 1817. Today Zwijnsbergen castle is privately owned.
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Frösöstenen is the northern-most raised runestone in the world and Jämtland's only runestone. It originally stood at the tip of ferry terminal on the sound between the island of Frösön and Östersund. The stone dates to between 1030 and 1050. It has now been relocated to the lawn in front of the local county seat due to the construction of a new bridge, between 1969 and 1971, on the original site.
Frösö runestone inscription means: Austmaðr, Guðfastr's son, had this stone raised and this bridge built and Christianized Jämtland. Ásbjörn built the bridge. Trjónn and Steinn carved these runes.