Lannion is a commune in the Côtes-d'Armor department in Brittany in northwestern France. It is a subprefecture of Côtes-d'Armor, the capit…Lannion is a commune in the Côtes-d'Armor department in Brittany in northwestern France. It is a subprefecture of Côtes-d'Armor, the capital of Trégor and the center of an urban area of almost 60,000 inhabitants.