Kastellholmen

Kastellholmen is an islet in the centre of Stockholm, Sweden. It belongs to the district of Skeppsholmen. It is connected to adjacent Skeppsholmen through the Kastellholmsbron bridge. 
Kastellholmen has an area of 31,000 m². Kastellholmen has previously been known as "Notholmen", "Lilla Beckholmen" and "Skansholmen". On the island there is a small castle, Kastellet, which was built between 1846-1848 under design by Swedish officer and architect Fredrik Blom (1781–1853). Kastellholmen, like Skeppsholmen, has been managed by the Swedish National Property Agency since 1993 and is part of the Royal National City Park.