It was the base of the Østfold Regiment, with defence related responsibilities for the east side of Oslofjord.

A temporary fortification had previously been built on the site during the Torstenson War (1644–1645) between Sweden and Denmark–Norway.

In 1716 the fortress was used by the naval hero Peter Tordenskjold when he attacked the Swedish fleet during the Battle of Dynekilen.

The fortress, under the command of Nils Christian Frederik Hals, capitulated on 4 August 1814.

The remaining military installations in Fredrikstad were closed in 2002 and today the fortress with its mix of old buildings and art exhibitions is very popular for visitors.