The Weser is a river of Lower Saxony in north-west Germany. It begins at Hannoversch Münden through the confluence of the Werra and Fulda. It passes through the Hanseatic city of Bremen. Its mouth is 50 km further north against the ports of Bremerhaven and Nordenham. The latter is on the Butjadingen Peninsula. It then merges into the North Sea via two highly saline, estuarine mouths.
It connects to the canal network running east-west across the North German Plain.
The river combined with the Werra – a dialectal form of Weser – runs 744 km. This makes up the longest river wholly in Germany. The Weser itself is 452 km long. The Werra rises in Thuringia, the German State south of the main projection of Lower Saxony.