Saint-Brieuc is a French commune located in Brittany, in the west of France. It is the prefecture of the Côtes-d'Armor and the most populous city in the department, with a population of more than 45,000 inhabitants (2015) known as the Briochins and Briochines. With 171,721 inhabitants (2013), the urban area of Brioch is the most populated in the department. The city gives its name to the bay of Saint-Brieuc.