WWII: Headquarters for Marine Artillerie Regiment 30 and the Hafenkapitän; a regional naval logistics and communication hub
Cold War: Headquarters for Narvik fortress and the naval defence district, and the garrison twon for Nes fortress
WWII: Naval battery MAA 2./516; initially equipped with four 15 cm UTO guns, later upgraded to 15 cm SK L/40 guns
Cold War (1946–1998): Re-armed with 12.7 cm SK C/34 casemated guns, connected to the coastal artillery’s largest subterranean complex
WWII: Torpedo battery MAB 6./516; upgraded in 1944 from twin 50 cm G7v tubes to triple 53.3 cm G7a configurations
Cold War (1945–1994): Modernised in 1981 with a fully subterranean bunker housing upgraded heavy torpedo systems
WWII: Hub split between the lighthouse (Flugwache, Marine-Signalstelle) and Langnesodden (searchlight, Küstenhorchanlage submarine hydrophone array array)
Cold War: Considered for a 15 cm battery; however, Nes was preferred to provide superior tactical depth, leaving Barøy unused.
WWII: Naval intelligence hub with Marine-Signalstelle, Funkstelle, tracking stations, and FuMO 1-3 Calais radar; defended by Flak and 7.5 cm Pak
Cold War: Nes fortress searchlight detachment; planned location for a fixed hydrophone array