Bouches-du-Weser (German: Wesermündungen) is the name of a département of the First French Empire in present Germany. It is named after the mouth of the river Weser. It was formed in 1811, when the region was annexed by France. Prior to the Napoleonic occupation; its territory was divided between the Free Hanseatic City of Bremen, the duchy of Oldenburg, and the Hanoverian Duchies of Bremen and Verden, the latter of which had intermittently been incorporated into the Kingdom of Westphalia in 1807. Its territory is part of the present German states Lower Saxony and Bremen. Its capital was Bremen (Brême). The département was subdivided into the following arrondissements and cantons (situation in 1812):
- Bremen, cantons: Achim, Bremen (4 cantons), Lilienthal, Ottersberg, Rotenburg, Syke, Thedinghausen and Verden.
- Bremerlehe, cantons: Beverstedt, Bremerlehe, Dorum, Hagen im Bremischen, Osterholz and Vegesack.
- Nienburg, cantons: Alt-Bruchhausen, Bassum, Hoya, Liebenau, Nienburg, Rethem, Stolzenau, Sulingen and Walsrode.
- Oldenburg, cantons: Berne, Burhave, Delmenhorst, Elsfleth, Hatten, Oldenburg, Ovelgönne, Rastede, Varel and Westerstede.
Its population in 1812 was 327,175.
After Napoleon was defeated in 1814, the département was divided between the Kingdom of Hanover, the Duchy of Oldenburg, and the Free Hanseatic City of Bremen.