Katanpää Fort was built as the northernmost link in a chain of sea forts by Peter the Great of Russia

In the mid-19th century, during the Crimean War, the island of Lypertö in the Kustavi archipelago had a telegraph station on the Katanpää peninsula. At the beginning of the 20th century, Russia chose this area as the northernmost part of a chain of coastal fortress built to protect the city of St. Petersburg.

The fort was situated along sea lanes. Its main tasks were to guard these routes, to secure naval traffic and to maintain communications. The archipelago was a natural protection zone when approaching from the sea.

Russian activities began on the island in the early 1910s. Prisoners from the eastern part of Russia, Manchuria, and Amur were brought to the island as manual labour. These prisoners built kilometres of paved cobblestone roads on the island. A rumour circulated among the local people of Kustavi that the Katanpää Fort was actually being built by Chinese women. This rumour began due to the unusual clothing and the long hair braids of the oriental prisoners.

The batteries of Katanpää.

Some local Finnish men were also hired for the construction work. The fort was equipped with cannon batteries, a railway and about twenty ornate Russian-style wooden buildings. Upon the fort’s completion, 120 soldiers and their families were stationed there.

Life at the fort was relatively isolated from the outside world and there are no written records of its early stages. Instead, only local lore tells about stories of unrest. According to rumours, murder was also committed at the fort.

The deactivated cannon of Katanpää.

The fort was transferred to the Finland state after independence

After independence, the fort, along with all its equipment was transferred to the new Finnish state. The Red Guards held the fort at the time of the Revolution and conditions were uneasy. After the situation calmed, the fort was transferred to the Coast Guard and the Finnish army.

With the exception of small skirmishes, the Katanpää Fort troops never participated in the war, and none of its building stock was destroyed. During the Winter- and Continuation Wars, the focus was more on aerial surveillance and making observations of the enemy.

The Finnish Coast Guard began operations on the island after the wars, when the fort was used as a training ground for military conscripts and as a sentry fort. There was also a prison on the island between 1930 and 1940. The number of prisoners in the whole of Finland peaked in 1930, due to crimes stemming from years of shortage, as well as alcohol prohibition (1919-1932). At most, there were about 100 prisoners at Katanpää, whose work was to mine rock from the island’s quarry.

After the mid-1990s, the last of the personnel serving at Katanpää were transferred. For the first time, the fort was without staff.

Defence armaments of Katanpää.

The secluded fort was opened to tourists through the ownership of Metsähallitus

In 1999, the Katanpää Fort was handed over to Metsähallitus, and the island, which had long been closed to the public, quickly became a popular destination. The island features numerous well-preserved Russian-era decorative wooden buildings, defence fortifications and four concreted cannon batteries with bunkers. Two gun batteries were built in the 1910s, with the remining two constructed in the 1950s. These cannons are no longer operational.

The remote location of Katanpää Fort has been one of the reasons for the conservation of its buildings. Some of the original buildings have since been renovated. Today, a local entrepreneur operates on the island.

Read more and learn about this location: Katanpää webpages. 

Why and how is this sited protected?

Katanpää Fort is the northernmost link of a chain of sea forts extending from the Gulf of Finland, built by Peter the Great of Russia. The island has original wooden buildings and defensive structures. It is protected by the Antiquities Act. More information in the Antiquities Register. (in finnish)

Due to its original preservation, the fort has also been defined as a nationally significant built cultural environment.


Katanpää has a spacious guest marina for private boats. The island can also be reached in summer by ferry from Kustavi and Uusikaupunki.

Check out the schedules on the Katanpää website.

Finnish Heritage Agency’s mapservice

N: 6733874 E: 181175 (ETRS-TM35FIN)