Siaröfortet is located on the island of "Kyrkogårdsön" west of Siarö in the Stockholm archipelago, at Furusundsleden, and represented together with Meadow Holm fort Vaxholms outer line of fortifications. The fort was initially planned to be constructed at Siarö, hence the name. They changed their minds, however, and was based instead on Kyrkogårdsön. The name comes Kyrkogårdsön that there was an ancient burial ground for cholera victims on the island. The facility consists of a head piece that is built in the mountain. The concrete roof has a thickness of four to six feet. The main armament consisted of two heavy 15.2 cm guns that came from the battleship HMS Svea (launched in 1885). At the beach were four 57 mm cannons and a large height adjustable 5000 watt floodlights. The entire eastern, northern and western sides were surrounded by barbed wire obstacles, whose remnants still remain. Inside the mountain, around 270 soldiers place, here were bedrooms, dining rooms, kitchens, toilets, office and storage room for food, water and weapons.