The Saar is a river that forms part of the border between France and Germany. It is 434 km long and flows through the Lorraine region of France and the Rhineland-Palatinate and Saarland states of Germany. The Saar is a tributary of the Moselle River, which it joins near Konz in Germany. The Saar is an important waterway for both countries, providing hydroelectric power, irrigation, and transportation.