Grønsalen or Grønjægers Høj is about 100 metres long and 10 metres wide, which makes it Denmark's largest long barrow and is widely recognised as one of Europe's outstanding ancient monuments. The barrow, rising over a metre above the surrounding area, is encircled by 134 large stones. The grave, at the centre, is covered with earth and contains three burial chambers, two of which are open. It is not known when they were first opened or what was found inside. The long barrow was examined in 1810 by Bishop Münter and was protected by law after that. On the basis of its shape, the barrow has been dated as Neolithic, approximately 3500 BC. The first historical reference to the site was in ca. 1186 when it was called Grónesund.References:
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.