Castrop-Rauxel, often simply referred to as Castrop by locals, is a former coal mining city in the eastern part of the Ruhr Area within the state of North Rhine-Westphalia in Germany.

Dortmund is the third-largest city in North Rhine-Westphalia, after Cologne and Düsseldorf, and the ninth-largest city in Germany. With a population of 612,065 inhabitants, it is the largest city of the Ruhr as well as the largest city of Westphalia. It lies on the Emscher and Ruhr rivers in the Rhine-Ruhr Metropolitan Region, the second biggest metropolitan region by GDP in the European Union, and is considered the administrative, commercial, and cultural centre of the eastern Ruhr. Dortmund is the second-largest city in the Low German dialect area, after Hamburg.