Erdre is a river in western France, tributary to the river Loire. Its source is in the département Maine-et-Loire, near La Pouëze. It flows through the départements Maine-et-Loire and Loire-Atlantique. It flows into the river Loire in the city Nantes.
The municipality of Nort-sur-Erdre (in Breton, Enorzh; 6,085 inhabitants - Nortais) is located on the river Erdre, 30 km north of Nantes and 40 km south of Châteaubriant.
The bridge on the Erdre was built in 1753-1775 by the architects Felix and Garbay de Dambois.
It is believed that the episode of Nort delayed the attack of Nantes by the Royalists and gave more time to prepare the defense of the city, contributing to the victory of the Republicans on 29 June 1793.
In the middle of the IIIrd century, a Gallo-Roman settlement was established near the rivers Erdre, Gesvres, Hocmard and Rupt, which water the current municipal territory of la Chapelle-sur-Erdre.
The green stripe recalls the woods, the hedges, the valleys and the meadows of the municipality, which is nicknamed 'the green lung of the city of Nantes'.
The blue stripe symbolizes the river Erdre as well as the other rivers which water the municipality.