Köthen was a district (Kreis) in the middle of Saxony-Anhalt, Germany.

At first the district Dessau-Köthen did cover the area surrounding the two district-free cities Dessau and Köthen.

In 1950 the city of Köthen was added to the district, and it was renamed after its capital.

The district is located in the Magdeburger Börde, with soft hills from the moraines from the last ice age.

The river Elbe forms part of the northern boundary of the district.