Dortmund is the third-largest city in North Rhine-Westphalia, after Cologne and Düsseldorf, and the eighth-largest city in Germany. With a population of 609,000 inhabitants, it is the largest city (by area and population) of the Ruhr as well as the largest city of Westphalia. It lies on the Emscher and Ruhr rivers (tributaries of the Rhine) in the Rhine-Ruhr Metropolitan Region 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.