The Eider (; ; Latin: Egdor or Egdore) is the longest river in the German state of Schleswig-Holstein. The river starts near Bordesholm and reaches the southwestern outskirts of Kiel on the shores of the Baltic Sea, but flows to the west, ending in the North Sea. The middle part of the Eider was appropriated for use as part of the Kiel Canal.

The Eider (; ; Latin: Egdor or Egdore) is the longest river in the German state of Schleswig-Holstein. The river starts near Bordesholm and reaches the southwestern outskirts of Kiel on the shores of the Baltic Sea, but flows to the west, ending in the North Sea. The middle part of the Eider was appropriated for use as part of the Kiel Canal.