The Sieg River is a tributary of the Rhine River in western Germany. It flows for about 150 kilometers, starting in the Sauerland region and winding through several towns, including Siegen and Düren, before joining the Rhine near Niederkassel. The river is known for its scenic landscapes and recreational opportunities. The Sieg River basin is characterized by lush forests and rolling hills, making it a popular destination for hiking and cycling. The river also supports various wildlife and is an important resource for local communities, providing water for agriculture and industry.