The Raseborg Castle was built during the Crusades, around the decade of 1370. It is located in Snappertuna of Raseborg, where there had been an island in the river. Nowadays the shrunk river runs nearby but the castle is surrounded by grassy lowlands.
The castle used to be an important regional center of government. The castle was a stronghold of the Swedish kingdom and a center of commerce in Finland. The 15th Century was the height of the influence of the castle, and during that time Charles VIII of Sweden stayed there for a while.
After Helsinki was founded and the beer cellar collapsed, the castle was abandoned around middle of 16th century and slowly fell into ruins after. The area kept its name and Raseborg became a county during the reign of Johan III. The castle has been repaired, at the earliest during the 19th century and the latest restoration took place around 1980s. Nowadays, the area is an location for events and during the summer it is open to visitors.