Katanpää Fortress

Katanpää Fortress is a military installation on an island in the Archipelago Sea that overlooks three shipping lanes. The site contains four concrete cannon batteries with bunkers along with wooden structures used for military purposes.

Russian forces built this fortress in the 1910s as the northernmost post in the Baltic Sea defense system. Prisoners from eastern Russia and Manchuria provided labor for the construction work.

The fortress displays Russian wooden structures from the early 20th century that reflect the architectural style of the period. These buildings show how the occupying forces built and organized their military settlement.

The island is accessible only by boat, with regular services departing from Uusikaupunki during summer months. Wear sturdy shoes as the ground is uneven and can be wet in places.

Between 1930 and 1940 the facility served as a military prison holding inmates under harsh conditions. After this period it was preserved and opened to visitors as a straightforward historical site.