The "Nied française" is the bigger of the two, with a length of 59 kilometres (37 mi), and its source is near Morhange. Another town on the "Nied française" is Pange. The other stream, the "Nied allemande" is 57 kilometres (35 mi) long, with its source in Seingbouse, east of Saint-Avold. Another town on the Nied allemande is Faulquemont.
The Nied itself is 55 kilometres (34 mi) long, of which 16 kilometres (10 mi) are in Germany. It flows through Bouzonville, and joins the Saar in Rehlingen-Siersburg.