Semnon

Semnon
The Semnon between Pléchâtel and Poligné.
Location
Country	France
Physical characteristics
Source
• location	Congrier
• coordinates	47°47′30″N 01°08′34″W
• elevation	90 m (300 ft)
Mouth
• location	Vilaine
• coordinates	47°53′59″N 01°45′25″W
• elevation	7 m (23 ft)
Length	73.3 km (45.5 mi)
Basin size	400 km2 (150 sq mi)
Discharge
• average	2.8 m3/s (99 cu ft/s)
Basin features
Progression	Vilaine→ Atlantic Ocean

The Semnon (French pronunciation: [sɛmnɔ̃]; Breton: Sevnon) is a 73.3 km (45.5 mi) long river in the Mayenne, Maine-et-Loire, Ille-et-Vilaine and Loire-Atlantique départements, northwestern France. Its source is in Congrier. It flows generally west-northwest. It is a left tributary of the Vilaine into which it flows between Pléchâtel and Bourg-des-Comptes.

Départements and communes along its course

This list is ordered from source to mouth:

• Mayenne: Congrier, Saint-Erblon, Senonnes
• Maine-et-Loire: Pouancé
• Ille-et-Vilaine: Eancé, Martigné-Ferchaud
• Loire-Atlantique: Fercé
• Ille-et-Vilaine: Thourie
• Loire-Atlantique: Soulvache
• Ille-et-Vilaine: Teillay, Ercé-en-Lamée, Lalleu, Tresbœuf, La Bosse-de-Bretagne, Bain-de-Bretagne, Pancé, Pléchâtel, Poligné, Bourg-des-Comptes