The district consists of the Wagrien peninsula between the Bay of Lübeck and the Bay of Kiel, the island of Fehmarn, the eastern part of the region called "Holsteinische Schweiz" (Holsatian Switzerland) and the northern suburbs of Lübeck.
Holsatian Switzerland is an area full of lakes and woody hills, which is shared with the adjoining district of Plön. The Bungsberg, though only 168 m in height, is the highest elevation in Schleswig-Holstein. The island of Fehmarn is the third largest island of Germany. Since 1963 it has been connected to the mainland by a suspension bridge.