The course of the German-Danish border was on ballot 10 February and 14 March 1920. Two months later, surveillance of the provisional border line began. On 15 June 1920, sovereignty for Northern Schleswig was transferred to the Kingdom of Denmark and the new border became valid. Nevertheless, the old border at Königsau/Kongeåen (The King’s Brook) was still monitored in parallel until November 1920.
The Danish border guards initially patrolled the border on foot in a light blue uniform. The German border guards and auxiliary customs inspectors, on the other hand, in their field-grey uniforms from the First World War, met with little goodwill from the population at the beginning.
During the Second World War, the border was closed by the German Wehrmacht, then by the British occupation forces until 1947. Some border crossings did not reopen until years later, some not at all. In 1955, border surveillance became more mobile. Motorbike patrols were introduced first, followed by car patrols four years later. From 1969, the hinterland was also systematically monitored. A real revolution was the introduction of camera surveillance of the border. While the German Federal Border Police searched the "green border" at night with thermal imaging cameras at certain points, the Danish police installed motion detectors and infrared cameras at the small border crossings. At present, since the opening of the border on 25 March 2001, (almost) only the hinterland has been monitored at all.
The Danish border guards initially patrolled the border on foot in a light blue uniform. The German border guards and auxiliary customs inspectors, on the other hand, in their field-grey uniforms from the First World War, met with little goodwill from the population at the beginning.
During the Second World War, the border was closed by the German Wehrmacht, then by the British occupation forces until 1947. Some border crossings did not reopen until years later, some not at all. In 1955, border surveillance became more mobile. Motorbike patrols were introduced first, followed by car patrols four years later. From 1969, the hinterland was also systematically monitored. A real revolution was the introduction of camera surveillance of the border. While the German Federal Border Police searched the "green border" at night with thermal imaging cameras at certain points, the Danish police installed motion detectors and infrared cameras at the small border crossings. At present, since the opening of the border on 25 March 2001, (almost) only the hinterland has been monitored at all.