Jutland peninsula is made up of the German Bundesland of Schleswig-Holstein. Schleswig-Holstein has two parts: the former duchies of Schleswig (Danish fief) and Holstein (German fief), both of which have passed back and forth between Danish and German rulers several times. The last adjustment of the Danish–German border followed the Schleswig Plebiscites in 1920 and resulted in Denmark's regaining Northern Schleswig ( or more commonly today: "Sønderjylland"). The historical southern border of Jutland are areas south of Kiel, Husum and Rendsburg, but the river Eider was the border between the former duchies of Schleswig and Holstein, as well as the historical
Jutland a breaching North Sea flood in 1825 created a coast to coast connection. This area is called the North Jutlandic Island, Vendsyssel-Thy (after its districts) or simply "Jutland north of the Limfjord"; it is only partly co-terminous with the North Jutland region. The islands of Læsø, Anholt and Samsø in Kattegat and Als at the rim of the Baltic Sea South are administratively and historically tied to Jutland although the latter two are also regarded as traditional districts of their own. Inhabitants of Als would agree to be South Jutlanders, but not necessarily Jutlanders. The Danish Wadden Sea Islands and