Ilmenau is a town in Thuringia, central Germany. It is the largest town within the Ilm district with a population of 38,600, while the district capital is Arnstadt. Ilmenau is located approximately 33 km south of Erfurt and 135 km north of Nuremberg within the Ilm valley at the northern edge of the Thuringian Forest at an elevation of 500 metres.

Thuringia, officially the Free State of Thuringia, is a state of central Germany, covering 16,171 square kilometres (6,244 sq mi), the sixth smallest of the sixteen German states. It has a population of about 2.1 million.