sûre

The Sûre is a river in western Europe, known in German as the Sauer and in Luxembourg and France as Sûre. It is a tributary of the Moselle and plays an important role in the hydrology of the region. The river rises in the Ardennes region near the Belgian border, flows southwest through northern Luxembourg, and for a stretch forms part of the Luxembourg–Germany border before entering Germany and joining the Moselle at Konz, opposite Trier.

Along its course the Sûre passes several towns, including Echternach and Diekirch, and it hosts the Upper Sûre Reservoir (Lac de la Haute-Sûre) in northwestern Luxembourg. This reservoir provides drinking water for Luxembourg and serves as a site for recreation and tourism. The river’s drainage basin covers parts of Belgium, Luxembourg, and Germany, and its waters support hydroelectric generation at multiple sites.

Etymology and usage: the name Sûre is the French designation for the river; in German contexts the river is typically called Sauer. The toponym is of ancient origin and has been used for centuries in the region. The Sûre valley has shaped settlement patterns and economic activity, and the river remains significant for ecology, water supply, and regional tourism.