Denmark–Germany border

The Denmark–Germany border (Grænsen mellem Danmark og Tyskland; Grenze zwischen Dänemark und Deutschland) is 68 km long and separates Denmark and Germany.

History
In the treaty of Heiligen year 811 the Eider was recognized as a border between Denmark and the Frankish Empire. As a swampy river, it formed a natural border. On the highest area near the watershed, it was dryer. The very old travel route Hærvejen went there, and a defense wall, Danevirke, was built there. Later the duchies of Schleswig and Holstein arose. Before 1864 Schleswig was a fiefdom of Denmark, while Holstein was a fief of the Holy Roman Empire (until 1806) and a member of the German Confederation (after 1815). Both territories were ruled by the Danish king in his additional role as Duke of Schleswig and Duke of Holstein (occasionally together with other Dukes, like the Gottorp Dukes). The border between the Danish fief of Schleswig and the German fief of Holstein still ran along the Eider, the boundary between the duchies and the Kingdom of Denmark ran along the Kongeåen and the southern boundary of the Danish monarchy (≈Helstaten) ran along the Elbe.

In 1864, Schleswig-Holstein was conquered by Prussia, and so an international border was created between Denmark and Germany/Schleswig-Holstein. It went from a place at the coast 5 km south of Ribe, rounded Ribe on 5 km distance, then went eastbound just south of Vamdrup, and just north of Christiansfeld to the Baltic Sea.

In 1920, the border was moved about 50 km southward to the present position, as determined by the Schleswig referendum in 1920. This approximately followed the not clearly defined language border.

Border controls
In 2001, all border controls were removed based on the Schengen Agreement.

In response to the Swedish border control due to the European migrant crisis, border checks were temporarily introduced starting 4 January 2016. Prime minister Lars Løkke Rasmussen cited fear of accumulation of illegal migrants in Copenhagen as one of the reasons for this decision. It was reported that the border controls at the German border cost the Danish tax payers 1.25 billion DKK (€167 million) from 2016 until mid-2019. They were never fully ended before the COVID-19 pandemic in early 2020, which caused renewed border closures throughout Europe.

To pass the border, an approved travel document is needed. This is mainly a passport. But also a national identity card from the European Economic Area is acceptable, although Denmark does not issue such cards, so a passport is needed for Danes.

Wild boar fence
In January 2019, the Danish government began constructing a fence along the border to keep wild boar, which can carry African swine fever virus, from crossing into Denmark. The 1.5 m high, nearly 70 km long fence—spanning the entire land border—was completed in December 2019 at an estimated cost of 30.4 million Danish kroner. The fence has created some protests. In May 2019 a volleyball tournament was held over the fence as a publicity event which was given some media attention. After completion there was a decision to raise it by adding wires over it, because animals like deer have been killed after being injured because of jumping over the fence.