A small territory caught between great powers
Åland's history is closely tied to the struggle for power in the Baltic. The islands' position in the middle of the sea route between Stockholm and the Gulf of Finland has given them a far larger role in Nordic history than their size would suggest. Two places in the municipality of Sund tell that story better than any others: the medieval Kastelholm Castle and the ruins of the Russian fortress of Bomarsund. They are not far apart and work perfectly as a day trip together.
Kastelholm Castle – a stronghold of the Swedish crown
Kastelholm Castle was built in the latter half of the 14th century and is first mentioned in writing in 1388. In the Middle Ages and early modern period it was one of the Swedish crown's most important fortresses in the Baltic region and the seat of royal administration on Åland. The castle has been rebuilt and damaged several times over the centuries, but what remains gives a clear picture of how power was exercised in the archipelago.
Today the castle is restored and open to visitors during the summer season. Right next to it is the Jan Karlsgården open-air museum, which shows how Åland farmers used to live – a good combination if you are travelling with children. Read more in our guide to the Åland Maritime Museum and Jan Karlsgården.
Bomarsund – a Russian fortress that was never finished
After Finland and Åland became part of the Russian Empire, Russia began building a vast fortress at Bomarsund in 1832. The plan was to create a military outpost on the empire's western edge, with fortified towers and barracks for thousands of soldiers. It was never completed.
During the Crimean War, a British-French fleet attacked Bomarsund in the summer of 1854. The fortress surrendered on 16 August 1854 and was blown up by the allied forces on 2 September the same year. After the war it was agreed that Åland must not be fortified again – the beginning of the demilitarisation that still defines the islands today. Read more about Åland's autonomy and demilitarised status.
Today the ruins lie scattered along the shore and through the woods, with information boards explaining what happened. The area is freely accessible and one of the most atmospheric places on Åland.
Planning your visit
- Start at Kastelholm in the morning and have lunch nearby before moving on to Bomarsund.
- Allow half a day to a full day for both sites, depending on how much you want to read and walk.
- Wear good shoes at Bomarsund, where the paths between the ruins can be uneven.
- Add a church – Sund has one of Åland's medieval churches. See our guide to medieval churches on Åland.
More history to discover on Åland
Kastelholm and Bomarsund are only the beginning. Saltvik has traces of Viking Age settlements and burial grounds – read more about Saltvik and Åland's Viking heartland. In Eckerö stands the grand Post and Customs House, a reminder of the time when the mail route between Stockholm and Turku crossed the Sea of Åland. And in Mariehamn, the maritime museum tells the story of the sailing-ship era that built the town's prosperity. Together, these places show how Åland went from royal outpost and military battleground to a demilitarised, self-governing island community.
Frequently Asked Questions
Q: How old is Kastelholm Castle?A: The castle was built in the latter half of the 14th century and is first mentioned in 1388. It is one of the oldest surviving buildings on Åland.
Q: Does it cost anything to visit Bomarsund?A: The ruins at Bomarsund are freely accessible all year round. Kastelholm Castle has seasonal opening hours and an admission fee, so check current details before your visit.