The northern department in the Kingdom of Westphalia, whose King was Jerome Bonaparte. It was added to the Kingdom in 1810. Formerly part of the Electorate of Hanover, it had been held by Prussia from 1805 until 1807, when the area had come under French occupation until its handover to the emperor’s brother.
The capital of the department was Hanover; its other leading town was Celle, which stands on the River Aller, a tributary of the Weser. The Aller flowed northwestwards across the department. In 1813-15 the lands returned to the Kingdom of Hanover.