The Weschnitz is a 58.9 km long right tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Rhine River running through the German states of Hesse

Hesse

Hesse or Hessia is both a cultural region of Germany and the name of an individual German state.* The cultural region of Hesse includes both the State of Hesse and the area known as Rhenish Hesse in the neighbouring Rhineland-Palatinate state...

 and Baden-Württemberg

Baden-Württemberg

Baden-Württemberg is one of the 16 states of Germany. Baden-Württemberg is in the southwestern part of the country to the east of the Upper Rhine, and is the third largest in both area and population of Germany's sixteen states, with an area of and 10.7 million inhabitants...

. The name of the river traces to the Celtic

Gallo-Roman religion

Gallo-Roman religion was a fusion of the traditional religious practices of the Gauls, who were originally Celtic speakers, and the Roman and Hellenistic religions introduced to the region under Roman Imperial rule. It was the result of selective acculturation....

 god Visucius

Visucius

Visucius was a Gallo-Roman god, usually identified with Mercury. He was worshipped primarily in the east of Gaul, around Trier and on the Rhine; his name is recorded on about ten dedicatory inscriptions. One such inscription has also been found in Bordeaux...

, who was worshiped in the region.

The river source is in the Odenwald

Odenwald

The Odenwald is a low mountain range in Hesse, Bavaria and Baden-Württemberg in Germany.- Location :The Odenwald lies between the Upper Rhine Rift Valley with the Bergstraße and the Hessisches Ried in the west, the Main and the Bauland in the east, the Hanau-Seligenstadt Basin – a subbasin of...

, in the town of Grasellenbach

Grasellenbach

Grasellenbach is a community in the Bergstraße district in southern Hesse, Germany.-Location:The community lies in the Odenwald and the UNESCO Geo-Naturpark Bergstraße-Odenwald at elevations between 420 and 580 m above sea level...

. It then flows in a westerly direction through a number of communities, including Fürth

Fürth, Hesse

Fürth is a community and a state-recognized recreational resort in the Bergstraße district in Hesse, Germany.- Location :The community lies in the UNESCO Geo-Naturpark Bergstraße-Odenwald on the Weschnitz, a small river that empties into Rhine near Biblis...

, Rimbach, Mörlenbach

Mörlenbach

Mörlenbach is a community in the Bergstraße district in southern Hesse, Germany.-Location:The community lies in the Odenwald some 25 km north of Heidelberg and about 30 km northeast of Mannheim, as well as lying 8 km southeast of Heppenheim...

 and Birkenau

Birkenau (Odenwald)

Birkenau in the Odenwald is a community in the Bergstraße district in southern Hesse, Germany. Its nickname is Das Dorf der Sonnenuhren – “The Sundial Village”.-Location:...

. At Weinheim

Weinheim

Weinheim is a town in the north west of the state of Baden-Württemberg in Germany with 43 000 inhabitants, approximately 15 km north of Heidelberg and 10 km northeast of Mannheim. Together with these cities, it makes up the Rhine-Neckar triangle...

, the river splits into two branches as it enters the Upper Rhine Plain

Upper Rhine Plain

The Upper Rhine Plain, Rhine Rift Valley or Upper Rhine Graben is a major rift, straddling the border between France and Germany. It forms part of the European Cenozoic Rift System, which extends across central Europe...

. The two courses join at Lorsch

Lorsch

Lorsch is a town in the Bergstraße district in Hesse, Germany, 60 km south of Frankfurt. Lorsch is well known for the Lorsch Abbey, which has been named a World Heritage Site.-Location:...

. It then flows through the communities of Einhausen

Einhausen

Einhausen is a community in the Bergstraße district in Hesse, Germany, some 15 km east of Worms.-Location:Einhausen lies on the Bergstraße in the Hessisches Ried and belongs the northeast Rhine valley, which has a rather favourable climate...

 and Biblis

Biblis

Biblis is a community in the Bergstraße district in southern Hesse, Germany.- Location :The community lies in the Rhine rift west of the Odenwald between Darmstadt to the north and Mannheim to the south; it also lies north of Bürstadt...

 before emptying into the Rhine at the Biblis Nuclear Power Plant

Biblis Nuclear Power Plant

The Biblis Nuclear Power Plant is in the South Hessian municipality of Biblis and consists of two units: unit A with a gross output of 1200 megawatts and unit B with a gross output of 1300 megawatts. Both units are pressurized water reactors...

.