Châteaubriant (French: [ʃɑtobʁijɑ̃] ⓘ; Breton: Kastell-Briant; Gallo: Châtiaoberiant) is a town in western France, about 350 km (220 mi) southwest of Paris, and one of the three sous-préfectures of the Loire-Atlantique department.

Châteaubriant is also situated in the historical and cultural region of Brittany, and it is the capital of the Pays de la Mée.

A part of the traditional province of Brittany, Châteaubriant also lies on the threshold of Anjou, and it was an important stronghold in northwestern France during the Middle Ages.

Châteaubriant played a certain role during the Mad War between France and Brittany and became a significant cultural centre in the 16th century, when the Renaissance château was built in the medieval fortress.

Châteaubriant lies at the north of the Loire-Atlantique département, in the middle of a triangle between Nantes, Angers and Rennes.

The main agricultural activities are forage and cereal growing, and cattle breeding (especially for beef and dairy production).

Several streams flow in the Chère in Châteaubriant: the Rollard, the Choisel and the Ruisseau du Pont-Pirraud.

The basin is limited by several hills belonging to the central axis of the Armorican massif which forms the Breton peninsula.

As "Châteaubriant" makes a reference to medieval lords, the town was renamed Montagne-sur-Chère ("hill on the Chère River").

[13] Châteaubriant has had at least three coats of arms: two primitive ones dating from the Middle Ages, and a modern one, adopted by the town council in 1890.

During the battle of Al Mansurah, an episode of the Seventh Crusade, the lord of Châteaubriant saved Louis IX of France.

The King permitted him to replace the pine cones with fleurs de lys, the royal French symbol.

Several menhirs are visible around Châteaubriant, notably on the communes of Rougé, Treffieux, Lusanger and Saint-Aubin-des-Châteaux.

[15] Their ethnicity is unknown, because the region is located at the border between several Gallic people, such as the Andecavi, the Redones and the Namnetes.

[18] The history of Châteaubriant itself began in the 11th century when Brient (an envoy of the Count of Rennes) built a castle on a motte bordering the Chère and Rollard rivers.

[19] The fortress of Châteaubriant was then a part of eastern Brittany's defensive line, known as the Marches of Brittany, along with the other walled towns of Vitré and Fougères (both in Ille-et-Vilaine) and Ancenis and Clisson (both in Loire Atlantique), which formed the first line of defense against the French Kingdom.

As the castle was in a very strategic location, the town was subject to several battles and invasions during the Middle Ages.

The treaty, which betrayed the authority of Francis II, was one of the reasons of the Mad War, and showed the weakness of the Duchy of Brittany as a political entity.

A new town hall and a covered market were also built, and the castle became a courthouse and the seat of the sous-préfecture.

Three railroads were built between 1877 and 1887 linking Châteaubriant with Nantes, Sablé-sur-Sarthe, Redon, Rennes and Ancenis.

In 1941, the prisoners were sent to Germany, and replaced by Gypsies, black market traffickers, prostitutes, and finally political activists, mostly Communists, treated as hostages.

Following the death of Karl Hotz, Feldkommandant of the Feldgericht of Nantes, killed by Resistants, 27 hostages were shot in a stone-pit outside the town on 22 October 1941.

[22] After the war, Châteaubriant was quickly rebuilt and extended towards the southwest, with the construction of a new industrial zone during the 1960s.

[20] Châteaubriant is located in the Pays de la Loire region, and in the sixth circonscription of the Loire-Atlantique département.

The town has been governed by left and right-wing mayors and if the citizens favored Nicolas Sarkozy as President in 2007, they massively voted for François Hollande in 2012.

In 2018, the functional area (aire d'attraction), which encompasses Châteaubriant plus 19 surrounding communes (636 km2 in total), had 33,961 inhabitants.

Industry is mainly represented by food processing, with the second biggest cattle market in France and an important slaughterhouse.

[25] The château de Châteaubriant is an important testimony to French medieval and Renaissance architecture.

The little town centre dates back to the Middle Ages, and several half-timbered houses are visible.

According to the legend, a beast, looking like a wolf, a pig or a big cat, prowls every night in the Béré suburb to protect a young maid who has been locked for centuries under the priory.