Bouches-de-l'Yssel (Dutch: Monden van de IJssel) was a department of the First French Empire in the present-day Netherlands. It was named after the mouth of the river IJssel. It was formed in 1810, when the Kingdom of Holland was annexed by France. Its territory corresponded with the present-day Dutch province of Overijssel. Its capital was Zwolle.
- Zwolle, cantons: Hasselt, Kampen, Steenwijk, Vollenhove and Zwolle.
- Almelo, cantons: Almelo, Delden, Enschede, Goor, Oldenzaal and Ootmarsum.
- Deventer, cantons: Deventer, Hardenberg, Ommen and Raalte.
Its population in 1812 was 145,000, and its area was 340,000 hectares.