Johannisborg, 17th century fortress ruins in Norrköping, Sweden

Johannisborg is a 17th century fortress ruin with surviving stone walls and one prominent tower located on the riverbanks of the Motala in Norrköping. Information panels throughout the site detail the original design and the role this structure played in the city's defenses.

Duke Johan of Östergötland laid the foundation on 3 May 1613 with 700 soldiers; the architect was Hans Fleming. The castle had three storeys, six towers and six spires, but was unfinished when the duke died in 1618. In 1719 it was so decayed that it could not stop the Russians from burning Norrköping, and from 1720 its stone and brick were reused in the town.

Queen Christina held Norrköping and Johannisborg as part of her maintenance lands after abdicating in 1654, with the right to appoint judges and officials and collect revenues. She stayed in the town and possibly the castle after the 1660 Riksdag, before leaving for the continent in spring 1661. On her death in 1689 the castle reverted to the Swedish crown.

The site is accessible year-round without advance booking and welcomes visitors freely. Take time to read the information panels scattered across the grounds to better understand the layout and its past.

The five-sided bastion earthwork is incomplete: only three corners remain, linked to the gate tower. The other two were dug away after Statens Järnvägar was granted permission in 1913 to build within the old castle grounds, and a postal terminal built in the late 1980s now blocks the view between tower and city.