On "Kyrkogårdsön", in the middle of Furusundsleden, is an idyllic archipelago island with red houses and a pine covered mountain. However, it hides a unique facility that was built in the early 1900s. The facility was supposed to be Sweden's most strategically placed defenses. Here would the defense of Stockholm start.

The fort was originally supposed to be on "Siarö" east of "Kyrkogårdsön" but were moved for various reasons to "Kyrkogårdsön" (Graveyard island) instead. Here was formerly an old graveyard for cholera victims, hence the name.


The decision to strengthen the Vaxholm fortress by building a fortification outside Vaxholm was taken in 1914 and 1916, work began to blast the rock for "Siaröfortet".

The work was far from trouble free and the contractor had great trouble both to keep schedules and strikes among the workers. The construction was delayed several times and eventually it was up to the Swedish Defense complete the fort themselfa.

Only in 1928 was the fort battle ready.


In normal cases, the enemy is the biggest challenge for a military facility but here there was another culprit that made it impossible for the fort to be working as planned, moisture and leaking water!


It made it unhealthy to reside in the mountain longer times why the conscripts wasn't allowed to sleep inside the mountain during peacetime. Moreover the first World War had ended, which was one of the reasons that it was planned and built, before it was finished which made the fort outdated even before it was completed.


The main facility is  blasted into the mountain and consists of several large rooms which have been covered with a 4-6 meter thick concrete roof. Down here there were central command, ammunition storage and logement for of up to 270 soldiers togehter with kitchens, toilets, offices, stores of food and water and armories.

The main armament consisted of two 152mm guns that came from the old battleship "Svea", placed in single towers. The cannons were manufactured by Bofors. In addition, there were two 57mm rapid-fire cannon on rails that could be placed in well-protected bunkers at the shoreline. In the mountain was even an hoistable 150cm, 5000W searchlight and a smaller searchlight, also on rails that was placed inside a bunker at the shoreline.

Access to these guns and searchlights were made through tunnels blasted into the rock that gave protection to the soldiers. Around the fort was also the trenches, also accessible through tunnels inside the facility. The entire northern, eastern and western shoreline was protected with barbed wire barriers which to some extent is still visible today. On the mountain's dome are two observation domes in steel for fire direction and control.


Since the plant has become outdated already at the beginning of the 2nd World War, it was taken out of service in 1939 and the defense moved further out in the archipelago. Siarö fort however, was used for various military exercises until 1959, after which it was mothballed and left to decay.

In the 1990s, a renovation began to restore of the old facility to a military museum, and in 2002 it got the status of national building monument.

Siarö fort is owned by the National Property Board, but managed by Blidösundsbolaget which also operates hostel and conference center in the cottages on the island.


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© Copyright: Swedish Spy Museum / Johan Öhgren