Fredriksvern
Larvik, Norway · built 1677
Fredriksvern (also called Friderichsværn (1801), Frederiksværn (1865), Fredriksværen (1900) and abbreviated Frsværn) was an important Norwegian naval base, just south of Larvik in Vestfold. It is named after Fredrik V Denmark-Norway. The town of Stavern has in many ways come to be because of this naval base.
Port data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).