In 1814, Chaumont was the unwitting witness to the end of the First Empire. On the 1st of March, Prussia, Russia, England and Austria signed an accord forbidding any individual peace deal with Napoleon the 1st, and to fight until his final defeat.
During World War II, Haute-Marne was split under the German occupation. The canal which runs from the Marne to the Saône served as a border, dividing the department into west and east. The east was a "reserved zone", intended for the creation of a new German state, whereas to the west would be the traditional "occupied zone". Haute-Marne was finally liberated by the Allies, in the form of the division of General Leclerc, between August an September 1944.
The highest mountain is Haut-du-Sac, in the Langres Plateau, in the southwest of the department, which rise to 516 m (1,693 feet). The lowest points at 117m are found on the plains of Perthois and Der.
The department is named after the Marne River, whose source is near Langres. This river covers 120 kilometres within the department. The department is to the east of the Parisian basin, and is characterised by a concentric sequence of cliff faces of varying geological origin, oriented northeast/southwest.