Northern Catalonia forms a triangle between the Pyrenees to the south, the Corbières Massif to the north-west and the Mediterranean Sea to the east. The Roussillon plain in the east, by far the most populated area, is formed by the flood plains of the Tech, Têt and Agly rivers (). The districts of Vallespir and Conflent cover the upper valleys of the Tech and the Têt respectively. The massif of the Canigou (), 2785 m, dominates much of the territory.