COTES-DU-NORD, a maritime department of the north-west of France, formed from the northern part of the province of Brittany, is bounded on the N. by the English Channel, on the E. by the department of Ille-et-Vilaine, on the S. by Morbihan, and on the W. by Finistere, and is situated between 48° 3' and 48° 57' N. lat. To the north the country is flat, but to the south it is rugged and undulating. A chain of granitic hills, the Monts du Menez, runs east to west through the department, dividing it into two unequal parts, of which the southern is the smaller.
Towards its western extremity this chain bifurcates to form the Montagnes Noires, to the south-west of the department, and the Montagnes d'Ares in Finist6re. The rivers of the Channel slope are the Rance, Arguenon, Gouessan, Gouet, Trieux, Treguier, and Leguer, while the Blavet, Mel, Oust, and Aulne belong to the southern slope. Off the coast, which is steep, rocky, and much indented, are the Sept-Iles, Brehat, and other small islands. The principal bays are those of St Malo and St Brieuc. The rocks of the district are granite, porphyry, gneiss, schist, and allied rocks, and workable slate and marble. Many of the plains on both sides of the chain of hills are sandy and sterile, and much of the soil is stony. The more important products are hemp, flax, cereals, wax, honey, lead, and iron ; the chief industries are the rearing of horses, sheep, goats, and cattle ; sea-fishing ; the manufacture of sail-cloth, linen, spun-wool, sugar, and paper ; and smelting and forging. The department is divided into the five arrondissements of St Brieuc, Dinan, Guingamp, Lannion, and Loudeac, which contain 48 cantons and 384 communes. The chief town is St Brieuc. Corseul, or Corseult, a small town of some 3000 inhabitants, six miles to the north-west of Dinan, is interesting for the Roman remains discovered there, and for its preservation of the name of the ancient Celtic tribe of the Curiosolit. The total area of COtes-du-Nord is 26581 square miles, and the population in 1872 was 622,295. Bas Breton is spoken in the arrondissements of Guingamp and Lannion, and in part of those of Loudeac and St Brieuc.