The City Municipality of Bremen is a Hanseatic city in northwestern Germany. A commercial and industrial city with a major port on the River Weser, Bremen is part of the Bremen-Oldenburg metropolitan area (2.4 million people). Bremen is the third most populous city in Northern Germany and tenth in Germany. Bremen is some 60 km south from the Weser mouth on the North Sea. With Bremerhaven right on the mouth the two comprise the state of the Free Hanseatic City of Bremen .