The Saar Protectorate (German: Saarprotektorat [ˈzaːɐ̯pʁotɛktoˌʁaːt]; French: Protectorat de la Sarre), officially Saarland (French: Sarre), was a French protectorate and a disputed territory separated from Germany. On joining West Germany in 1957, it became the smallest "federal state" (Bundesland), the Saarland, not counting the "city states" (Stadtstaaten) of Berlin, Hamburg, and Bremen. It is named after the Saar River.
The region around the Saar River and its tributary valleys is a geologically folded, mineral-rich, ethnically German, economically important, and heavily industrialized area. It has well-developed transportation infrastructure, and was one of the centres of the Industrial Revolution in Germany. Around 1900, the region formed the third-largest area of coal, iron, and steel industry in Germany (after the Ruhr Area and the Upper Silesian Coal Basin). From 1920 to 1935, as a result of World War I, the region was under the control of the League of Nations as the Territory of the Saar Basin. In 1935, Nazi Germany established its full sovereignty over the territory.