The Hohenfelder Mühlenau is a stream, about 10 km (6.2 mi) long, in the district of Plön in northeast part of the North German state of Schleswig-Holstein.

It is interrupted by two barriers, the mill at Köhn, which has fallen into ruins leaving just a foundation behind, and poses an obstacle of 2 to 3 metres (7 to 10 ft).

This hurdle will now be bypassed, in line with the EU Water Framework Directive, using a drop structure (Sohlgleite) which will be built next to the existing building.

The Hohenfelde Mill is another obstacle of about 4 metres (13 ft), which is partly bypassed with a fish pass.

At the end of its course the Hohenfelder Mühlenau discharges into the Baltic Sea with a water quality class of I-II.