Southern Schleswig (German: Südschleswig or Landesteil Schleswig, Danish: Sydslesvig) is the southern half of the former Duchy of Schleswig[1] in Germany on the Jutland Peninsula. The geographical area today covers the large area between the Eider river in the south and the Flensburg Fjord in the north,[2] where it borders Denmark. Northern Schleswig, congruent with the former South Jutland County, forms the southernmost part of Denmark.