The Lahn is a river in western Germany, flowing approximately 245 kilometers (152 miles) through the states of Hesse and Rhineland-Palatinate. It originates in the Lahn Mountains and eventually merges with the Rhine River near Lahnstein. The river is known for its scenic beauty and is a popular destination for outdoor activities such as hiking and cycling along its banks. Historically, the Lahn played a significant role in trade and transportation, particularly during the Middle Ages. It was navigable for small boats, facilitating the movement of goods and contributing to the development of towns along its route, including Wetzlar and Marburg. Today, the river remains an important ecological and recreational resource.