most important valley in the Gaspé Peninsula, lying in Bas-Saint-Laurent region, eastern Quebec province, Canada. Extending in a northwest-southeast direction for some 60 miles (100 km), it forms a direct lowland route through the Notre Dame Mountains from the St. Lawrence River to Chaleur Bay on the Atlantic. The valley is drained by the Matapédia River, which flows 50 miles (80 km) from Lake Matapédia (14 miles 【23 km】 long by 2 miles 【3 km】 wide) to the Restigouche River (Matapédia is Indian for “joining of two rivers”); both the river and the lake are noted for their salmon fishing and scenic beauty. Part of the valley's interior lies within Gaspesian Provincial Park.

The valley floor is a fertile dairying and mixed-farming area, the centres of which are the agricultural market towns of Sayabec, Amqui, and Causapscal. In addition to its attraction for farmers, tourists, and sportsmen, the valley serves as an important transportation route between the Maritime Provinces and the Canadian mainland; through it passes the Canadian National Railway and a main provincial highway. New settlements in the interior include Saint-Thomas de Cherbourg and Saint-Jean de Cherbourg.