A strategically important location
Looking at a map of the Baltic Sea region, it is easy to understand why control over the Hanko Peninsula has been contested. From Hanko, it was possible to monitor and control maritime traffic in the northern Gulf of Finland—both commercial and military. This made it a coveted strategic outpost, held at different times by Sweden, Russia, the Soviet Union, and Finland.
Gustavsvärn is the largest and best-preserved part of Hanko’s historic four-part fortress. On the mainland, the Queen’s Hill (Kuningattarenvuori) guarded the sea, while the islands of Gustavsvärn, Meijerfeldt, and Kustaa Aadolf were fortified. Few traces remain on the mainland today, but fortifications and defensive walls can still be found on the islands of Kustaa Aadolf and Gustavsvärn.
The island also features a later-built lighthouse and fog signal station, representing the newer traditions of maritime navigation.
Gustavsvärn – Guardian of Hanko
The Gustav War between Sweden and Russia (1788–1790) ultimately highlighted the importance of Hanko’s harbour in the battle for dominance over the Gulf of Finland. The temporary field fortifications built by the Swedes on Tulliniemi and its nearby islands were to be replaced with permanent bastion fortresses. In spring 1792, the regent, Duke Charles, ordered the planning of new fortifications at Gustavsvärn, Kustaa Aadolf, and Queen’s Hill.
Small islets fortified to guard Hanko harbour
The task of designing the fortress was assigned to Brigadier General von Kierting of the engineering corps, assisted by Captain Carl Nycander. Construction began in spring 1793. The primary objective was to guard the entrance route to Hanko harbour. The idea was to destroy the enemy at sea or at least inflict such losses that they could not reach the harbour within artillery range. The fortresses of Gustavsvärn and Kustaa Aadolf, built on small islets, were to protect the harbour with crossfire. Work continued into the early 1800s but ultimately remained incomplete.
The Gustavsvärn fortress was largely built from the island’s own red granite. Evidence of quarrying is still visible. The island’s topography was used in the fortress design—besides strategic viewpoints, the placement of the walls followed the terrain. Building walls on top of steep cliffs added several metres of height. Some natural rock faces were even cut to make them steeper.
The Russians continued the work—Then demolished the fortress
In spring 1808, the fortress was surrendered to the Russians without a fight. The Russians saw its continued strategic importance and resumed construction. The Crimean War (1854–1855) accelerated these efforts. On the eve of the war, Gustavsvärn was said to have 61 cannons. The fortress fulfilled its purpose by repelling an attack by the British.
After the war, the fortress was deemed too expensive to maintain given its military value. In late summer 1854, the fortifications of Gustavsvärn, Kustaa Aadolf, and Meijerfeldt were demolished. The destruction was furthered by granting local residents permission to salvage building materials from the garrison area.
World War II in the Hanko archipelago
During the Winter War, Hanko was one of Finland’s most heavily bombed cities, and the old fortress also suffered damage. After the war, Finland was forced to lease the Hanko Peninsula to the Soviet Union for 30 years. The Soviets dug bunkers within the walls of Gustavsvärn, although these have since been removed. During the Continuation War, fierce fighting took place in the archipelago near Hanko. The leased territory was returned to Finnish control on 4 December 1941.
A fascinating place to visit
The Gustavsvärn fortress island is an intriguing maritime military history site, but visitors should exercise great caution due to the poor condition of some walls. The safest way to explore is to follow the path leading from the pier to the inner courtyard.
The former fog signal keeper’s house and its surroundings have been leased to [the Finnish Lighthouse Society (majakkaseura.fi, in Finnish)]https://www.majakkaseura.fi/). In summer, the society sells souvenirs such as the History of Gustavsvärn, postcards, and lighthouse posters from the house.
Gustavsvärn is open all year round, but maritime weather conditions may limit access. The island is unstaffed and has free public access. A guest pier is available.
In Hanko’s Eastern Harbour (Itäsatama), local tourism companies offer regular summer waterbus cruises to Gustavsvärn. More information is available on the City of Hanko’s website: visithanko.fi.
Learn more: History of Gustavsvärn (majakkaseura.fi, in Finnish).
