The Côtes-d'Armor are located in Brittany. This is another department created during the French Revolution in a part of the former province of Brittany, composed of the bishoprics of Brittany, Cornwall, Trégor, Saint-Brieuc, the north-east of the bishopric of Doll and two northern parts of the bishopric of Vannes.
For two centuries, the department was called the North Coast. Long criticised, this name was changed in 1990 to the current, more precise one, which literally means “the coastal region”.
The department borders Finistère, Morbihan, Ille et Vilaine and La Manche. Its maximum altitude is 348 metres with Mont Bel-Air and its largest lake is Lac de Guerlédan, shared with Morbihan.