Carlsten Fortress

After Marstrand became Swedish in 1658, King Charles X Gustav recognized the need to protect the ice-free port. An initial provisional wooden structure was built in 1658, which already repelled a Norwegian attack in 1659. From 1666, this was replaced by a rhomboid redoubt, which was extended between 1671 and 1673 by a square tower, the Carlsten. This tower formed the core of the later citadel. In 1677, the fortress briefly fell to Danish-Norwegian troops. Extensive expansion work began in 1681, concluding in 1685 with a round, multi-story tower and a moat. Despite these reinforcements, the fortress capitulated in 1719 after an attack by the Norwegian Admiral Peter Tordenskiold. After its return in 1720, damages were repaired, and further battery works and a lighthouse were installed. Further reinforcements followed until 1851. With the advent of steam navigation and the decreasing threat of war against Denmark, Carlsten lost military importance. In 1882, the garrison was withdrawn. Nevertheless, the fortress served military purposes in the First and Second World Wars and during the Cold War before the military finally left it in 1991. For the construction of the fortress, the so-called “Marstrand work” was introduced, a forced labor for convicts, which lasted until 1854. One of the most famous prisoners was the thief Lasse-Maja, who was pardoned in 1839.

Carlsten Fortress is located in Marstrand, in the Kungälv district, in the Västra Götaland region of Sweden. It is situated at an elevation of approximately 40 meters above sea level.

Carlsten Fortress is open to visitors today and can be explored.

• Bohus Fortress (Fortress), approx. 25.1 km away
• Nya Elfsborg Fortress (Fortress), approx. 27.2 km away
• Älvsborg Fortress Remains (Fortress), approx. 29.3 km away
• Gothenburg Cathedral (Sacred Building), approx. 30.6 km away