The Duchy of Nassau was an independent state between 1806 and 1866, located in what became the German states of Rhineland-Palatinate and Hesse. It was a member of the Confederation of the Rhine and later of the German Confederation. Its ruling dynasty, later extinct, was the House of Nassau. The duchy was named after the Nassau Castle, itself after its historical core city, Nassau, although Wiesbaden rather than Nassau was its capital. In 1865, the Duchy of Nassau had 465,636 inhabitants. After being occupied and annexed into the Kingdom of Prussia in 1866 following the Austro-Prussian War, it was incorporated into the Province of Hesse-Nassau. The area is a geographical and historical region, Nassau, and Nassau is also the name of the Nassau Nature Park within the borders of the former duchy.
- Country
- German Confederation, Confederation of the Rhine
- Inception
- 1806
