Northern Catalonia forms a triangle between the Pyrenees to the south, the Corbières to the north-west and the Mediterranean Sea to the east. The Plain of Roussillon in the east, by far the area where more people live, is formed by the floodplains 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 mountain Le Canigou (), , dominates much of the territory.