Älvsborg Fortress (Swedish:Älvsborgs fästning), with its main facilityOscar II's Fort (Swedish:Oscar II:s fort) built 1899–1907,[1] is a now-defunct Swedish fortification located at the mouth of theGöta River in theÄlvsborg district ofGothenburg, Sweden.
Construction of the fortress began in 1899 and was completed in modern condition in 1907. In 1904 the name Älvsborg Fortress was given to the new coastal fortress at the mouth of theGöta River, whose strongest fortification, Oscar II's Fort, started construction in 1899 on Västerberget. The fortress, whose task, like previous fortresses, was to secure bothGothenburg and thePort of Gothenburg and theSwedish Navy's rallying point there against attacks from the sea, was in 1907 equipped with new modern artillery guns. The main body of the fortress consisted of two 24 cm guns model of 1904 mounted ondisappearing carriages and some 15 cm gun turrets and other light guns.[2] The fort, which is immersed in thebasement, encompasses space for 300 people and consists of several hundred meters of walkways with offices, lodgings,messes and stores.[3] The fort's armament was completed in 1907. In addition to naval mines around the flanks, there was also a light battery, theGötiska batteriet ("Geatish Battery") donated by theGeatish Society.[2]
On KingAlbert I of Belgium's arrival and departure from Gothenburg in connection with the visit of the thenCrown Prince Leopold's wedding toPrincess Astrid on 4 November 1926, a greeting was fired from Älvsborg Fortress. This was at the same timeKA 3's farewell salute and the last salute given by Älvsborg Fortress. On 1 November of the same year, the fortress had already been placed into materiel reserve.[4] Prior to the threatening foreign policy situation, the fortress was put in the defensive state in the fall of 1939. Oscar II's Fort lost its guns in 1939-1940 with the exception of theGötiska batteriet, when they were moved to the main defense line on the outskirts ofGothenburg archipelago. DuringWorld War II, the fortress and the fortress area were used for accommodation, etc. In 1942, Älvsborg Fortress was amalgamated intoGothenburg Coastal Artillery Defence, which, with its fortifications, batteries and mine barriers in the Gothenburg archipelago, took over the traditional defence of Gothenburg. Until the 1970s, the fortress spaces were used for storage. Due to a significant deterioration of the internal passages and spaces, the fortress was completely disbanded during the 1970s.[2]
The fortress became alisted building on 15 March 2018.[5]

Staffing:[2]
Commandants:[6]
57°40′29″N11°51′8″E / 57.67472°N 11.85222°E /57.67472; 11.85222