Älvsborg or Elfsborg may refer to: Military. Fortresses. Old Älvsborg, a ruined mediaeval castle on the Göta River in Gothenburg, Sweden. New Älvsborg, a sea fort on the island of Kyrkogårdsholmen in Gothenburg, Sweden. Älvsborg Fortress, a 19th-century fortress at the mouth of the Göta River. Fort Nya Elfsborg, a 17th-century colonial fort on the Delaware River in modern New Jersey. Other military uses. HSwMS Älvsborg, a minelayer of the Swedish Navy. Älvsborg Regiment, a former infantry regiment based in Borås.
https://en.wikipedia.org/wiki/%C3%84lvsborg