The Lahn is a river in Germany. It has its source at the Ederkopf mountain in the Rothaargebirge, the highest part of the Sauerland. After 242 km it meets the Rhine at Lahnstein . Important cities at the Lahn include Marburg, Gießen and Limburg.
Lahn was also the name of a city which was created on January 1 1977 when the two cities Gießen and Wetzlar were merged. It was named after the river, to make the merger a merger of equals. However as the merger was very unpopular as well as inefficient -- it had been imposed on the cities against the will of almost all inhabitants -- it was reverted on July 31 1979, so the city Lahn only existed for 2.5 years.