The Free State of Thuringia is a state of Germany, located in the central part of the country. It has an area of 16,171 square kilometres (6,244 sq mi) and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states. Most of Thuringia is within the watershed of the Saale, a left tributary of the Elbe. Its capital is Erfurt.
The most conspicuous geographical feature of Thuringia is the Thuringian Forest, a mountain chain in the southwest. The Werra River, a tributary of the Weser River, separates this mountain chain from the volcanic Rhön Mountains, which are partially in Thuringia, Bavaria, and Hesse. In the northwest, Thuringia includes a small part of the Harz. The eastern part of Thuringia is generally a plain. The Saale River runs through these lowlands from south to north.