Forêts was a department of the French First Republic, and later the First French Empire, in present-day Belgium, Luxembourg and Germany. Its name, meaning 'forests', comes from the Ardennes forests. It was formed on 24 October 1795, after the Southern Netherlands had been annexed by France on 1 October. Before the occupation, the territory was part of the Duchy of Luxembourg and the Duchy of Bouillon. Its capital was Luxembourg City.
After Napoleon was defeated in 1814, most of it became part of the United Kingdom of the Netherlands, with the part on the east side of the rivers Our and Sauer becoming part of Prussia (now Germany). The territory is now divided between the Grand Duchy of Luxembourg, the Belgian province of Luxembourg, and the German state of Rhineland-Palatinate.
The department was subdivided into the following arrondissements and cantons (situation in 1812):
Its population in 1812 was 246,333, and its area was 691,035 hectares.
The administrative, institutional, economic, social, and political framework of Luxembourg was swept away without restraint. Unlike a simple transfer of sovereignty, such as Luxembourg had experienced many over the previous decades, this period was to put Luxembourg and surrounding areas on the path to a new kind of society.