Rendsburg is a town on the River Eider and the Kiel Canal in the central part of Schleswig-Holstein, Germany. It is the capital of the Kreis (district) of Rendsburg-Eckernförde. As of 2006, it had a population of 28,476.

The Neumünster Flensburg Railway is part of the Jutland line, the main north–south rail link through Schleswig-Holstein, Germany. Together with the line to Husum, which diverges in Jübek, and the line to Kiel, which diverges in Rendsburg, it also serves as an important east–west axis between Kiel and the Marsh Railway on the west coast. It consists of several sections that were parts of the first railways in the current territory of Germany.