Castelholm Castle is first mentioned in the annals in 1388 as "Dom Kastelholm". The exact date of the castle's foundation, however, is unknown. From the end of the 15th century the castle was the administrative centre of the archipelago and played an important strategic role. Archipelago and was also the hunting castle of the Swedish queen.
In its present appearance, the castle is a complex architectural complex, built and expanded between the late 14th and mid-17th centuries. In 1745 the castle suffered a devastating fire. It was only in the 20th century that it was restored.
There are two museums open next to the castle. One is the Museum of the State Prison Vita-Björn, located in the old prison building. The second is the Jan Karlsgården Open Air Museum Jan Karlsgården Open Air Museum, where more than twenty traditional Åland houses and mills can be viewed. Aland houses and mills from the 19th century. At the old inn, visitors are treated visitors are treated to national specialities.
