Boden Fortress () is a modern fortress consisting of several major and minor forts and fortifications surrounding the city of Boden, Norrbotten, in northern Sweden. The fortress was originally intended to stop or delay attacks from the east or coastal assaults, which at the time of construction meant Russian attacks launched from Finland. It was primarily the expansion of the railway network in Norrland, which in turn was a consequence of the rising importance of the northern iron ore fields, that led to the increased strategic value of northern Sweden and the construction of the fortress. Although the main forts were finished in 1908, many of the supporting fortifications were not completed until the start of the First World War. Improvements were also continuously made during, and between, both World Wars.
Boden Fortress is made up of five primary self-supporting forts excavated out of the bedrock in five of the mountains surrounding Boden: Degerberget, Mjösjöberget, Gammelängsberget, Södra Åberget and Rödberget. Eight fortified secondary artillery positions were constructed between the forts to give flanking support and to cover areas not in range of the main forts' artillery. In addition, 40 bunkers for infantry, along with dugouts and other fortifications, were built to cover even more terrain. During the Second World War anti-tank gun emplacements and additional bunkers and shelters were built, and tens of kilometres of dragon's teeth were placed around the fortress and the city itself. Owing to the end of the Cold War and the reduction of the threat from the Soviet Union, Boden Fortress became less important to the defence of Sweden, and began to be decommissioned. The last fort of the complex was decommissioned on 31 December 1998, and is now used as a tourist attraction. All five forts as well as some of the supporting structures have been declared historic buildings, to be preserved for the future, by the Swedish government.
Background
Central and peripheral defence
The two dominating theories of how to use fortifications in the operational perspective during the 18th and 19th centuries were the central fortress system () and the peripheral fortress system (), the latter also called the cordon system. The two systems were also known as central defence and peripheral defence. The peripheral defence theory was based on building smaller fortifications in advance positions to meet the enemy at an early stage, while the central defence theory was meant to weaken the enemy step by step in minor skirmishes and ambushes carried out by forces supplied and supported by central fortresses not located in the front line. In short, one theory advocated many minor fortifications built to directly engage the enemy, while the other advocated only a few major fortifications built not to directly engage the enemy, but to support the troops that engaged the enemy.The meaning of these two terms have shifted over the years. In the military terminology of the 19th century, the theories were mainly applied at the operational level, which means that both systems could be used for the defence of a country at the same time but at different theatres of war. From the late 19th century and onwards, the terms were used in a wider context, being applied mainly at the grand strategic level, thus making the two systems mutually exclusive rather than complementary for the defence of a country. This has spurred confusion as a fortification built for central defence—by the early usage of the term—in the outer portions of a country can be seen as a fortification built for peripheral defence—by the late usage of the term. See Nyström & Skeppstedt 1990, pp. 29–40 and pp. 75–78 for a discussion on this and examples of the early usage, see Nelsson 1993, p. 89 and Bergmark 1980, p.517 for two examples of the terms in late usage applied to Boden Fortress. This article uses the terms in their original, operational, meaning.
In the beginning of the 19th century the peripheral system—at least in Sweden—was deemed unmodern, due to the extremely long border and coastline of the country, which required a lot of personnel to maintain and support, leading to high costs and a neglect of the more mobile armed forces. The peripheral system was also meant to contain the enemy to a specific area, the coast and borders, but as time went and new tactics were taken into practice, the thin line of fortifications would be easily penetrated by the enemy forces, and when the enemy had advanced through the peripheral line, there would not be enough troops in the hinterland to stop the attacker. The central fortress system was better adjusted to defence in depth, it was not until the enemy attack had reached its culminating point that full counter-attacks would be launched. The central defence had also proven effective in the Seven Years' War—used by Frederick II of Prussia—and in Napoleon's Invasion of Russia—used by the Russians. Carl von Clausewitz, in his military treatise On War, even mentioned Sweden's good conditions for this kind of war of attrition:
The fourth principle, the Assistance of the Theatre of War, is naturally an advantage on the side of the defensive. [...] the army on the defensive continues to keep up its connection with everything, that is, it enjoys the support of its fortresses, is not weakened in any way, and is near to its sources of supply. [...] The campaign of 1812, gives as it were in a magnifying glass a very clear illustration of the effect of the means specified under principles 3 and 4. [...] It is true that with the exception of Sweden there is no country in Europe which is situated like Russia, but the efficient principle is always the same, the only distinction being in the greater or less degree of its strength.
Fortification of Sweden Sweden had just lost one third of its population, as Russia had conquered the eastern part and created the Grand Duchy of Finland out of it during the Finnish War in 1808–1809. Shortly after, in 1814, the west flank had been secured by the personal union with Norway, and after the Napoleonic Wars, the former main enemy of Sweden in the south, Denmark, was no longer any threat. The only threat left was Russia, which now stood just across the border in the north, and had possession of the Åland Islands less than 150 km from the Swedish capital Stockholm. The Swedish Navy was considered superior to the Russian in the Gulf of Bothnia, so a seaborne invasion against the coast of Norrland was not likely. And even though the Russians had invaded northern Sweden via Finland in the previous war, the general opinion was that in case of a new war, their main attack would be conducted towards Stockholm and southern Sweden.
This opinion led to the thought of finding a good rear defence area where the Estates and the Swedish government could move if the capital was in danger. This in turn naturally strengthened the central defence theory. The core land () would be the place from where the main part of the field army would conduct its operations, supported by a few fortresses. The area between the two large lakes of Vänern and Vättern was the choice for this core land, with approximately the same border as Skaraborg County. Sweden above the province of Dalarna was not even considered to be included in this strategy. The realisation of the middle Sweden central defence system was finally made 5 February 1819 when King Charles XIV John decided that one main fortress, the central fortress, and two smaller "operational fortresses" were to be built. The central fortress became Karlsborg Fortress at Karlsborg, while the two operational fortresses meant to be located at either end of Vättern never were built due to lack of funds.
While Norrland was not supposed to be included in this main central defence strategy, studies on how to defend this major part of the country were still conducted. However, northern Sweden was generally considered of very limited military interest and unsuitable for larger military operations due to the bad state of most of the roads, the large uninhabited areas, the large rivers and the very limited economical gain that the lands provided. The first of these studies, laid down by the Fortification Committee of 1819 ()—which was largely influenced by the committee's secretary Johan Peter Lefrén—led to nothing more than the opinion that the large rivers up north—especially the Ångerman River—would benefit the defence and that no major fortifications were to be built. In another study from 1824, colonel—and much later Swedish Minister for War—Gustaf Oscar Peyron suggested that it would be better to fortify positions just south of Boden—along the more northern Lule River—for example at Sävast or Avan. However no major changes were made, partially due to the limited military interest, but also because of the large amounts of money that was spent on building Karlsborg Fortress and modernizing other older fortifications in southern Sweden.
Railroads speed up planning
It was not until fifteen years later, when yet another committee—the Coastal Fortification Committee of 1839 ()—studied the defence of Norrland, that the Swedish Armed Forces started to focus a bit more on the northern provinces. This study however mainly presented plans for middle Norrland, and the provinces of Medelpad, Ångermanland and Jämtland. Those provinces had a more significant role as it was there that the main roads of Sweden started to intersect with the road network of Norway, which at the time was allied with Sweden. The road network north of this area consisted of the large coastal road—the only major north–south road—from Haparanda and all the way through Norrland down to Gävle. All the other major roads exclusively ran southeast–northwest—following the run of the large rivers—before ending in wilderness and thus did not provide any route further west into Norway and on to the Atlantic coast. The plans to strengthen Norrland by building a central fortress either on Frösön outside Östersund, or closer to the coast at Borgsjö outside Ånge, once again fell flat due to lack of money and lower priority compared to fortifications in southern Sweden.