Bohus Fortress (also Baahus or Båhus, originally: Bagahus) lies along the old Norwegian - Swedish border in Kungälv, Bohuslän, Sweden, north east from Hisingen where the Göta river splits into two branches (20 kilometres north of Gothenburg). It commands its surroundings from a cliff 40 metres high, with the river forming a natural moat around it.