The Aare is a tribuatry. Another option is Ruhr as a 4-letter tributary of the Rhine.
The answer is the Aar (another accepted spelling for the Aare.)
It does not flow into a sea. It is a tributary of the Rhine River.
The Ruhr is a 217 Km long river in western Germany and is a tributary of the Rhine. It flows into the Rhine in Duisburg.
Amongst others - Madon, Terrouin, Moselotte, Dhron.
The river Rhine has approximately 40 different tributaries. These include the Main, Mosel, Neckar, and Meuse. the Mosel is the longest tributary.
Oka
Saône.
Rhine
rhur
The longest river in Switzerland is the Rhine (375 km - 233 miles). The Rhine also flows through Germany, Austria, Liechtenstein, France and the Netherlands. The longest river that flows entirely in Switzerland is the Aar (295 km - 183 miles). It is a tributary of the Rhine.
Could be the Drome, the Cottey, the Doron, the Isere, the Seran, the Veore, the Saone.
The Moder River is located in Europe. Although it originates in Germany, it primarily runs through the country of France in the northeastern area and is a tributary of the Rhine river.