The Natashquan River is entirely within the Grenville geologic province of the Canadian Shield, characterized by a hilly plateau, ranging in altitude from to, and consisting offelsic and metamorphic rock, clastic rock and schists in the lower portion, with a few intrusions of mafic rock in the central part. The river largely runs through narrow valleys, and is fed by about 30 tributaries, of which the most significant are in downstream order: the Lejamtel, Mercereau, Mahkunipiu, Mistanipisipou, East Natashquan, Pehatnaniskau, Doré, West Natashquan, and Akaku Rivers. The last of the river forms a large sandy estuary, separated from the gulf by Natashquan Point and Cape Tiennot. Sainte-Hélène Island is located at the very mouth of the river. The climate of the basin is subarcticcontinental, with a short growing season. The upper portion has a cold subhumid climate, whereas the lower part is humid.
History
In 1534, Jacques Cartier sailed by the area and named Cape Thiennot after a ship captain that had settled at that location. The river was mapped in 1684 by Louis Jolliet who called it "Noutascoüan". Jacques-Nicolas Bellin identified it as "Grand R. Natachquoin" on his map of 1744, while the 1776 map by Carver showed "Great Natashkwen". From as early as 1710, a trading post was established on the left bank of the Natashquan River and later on the opposite bank to conduct fur trade with the indigenous Innu people. The post was acquired by the Hudson's Bay Company in the middle of the 19th century, but abandoned circa 1914 due to lack of profitability. A bridge carrying Quebec Route 138 across the river was opened on September 26, 2013.
Conservation
An area of is being considered for protection in a biodiversity reserve. The reserve, mostly within the Petit-Mécatina unorganized territory, will extend along the Natashquan River southward from the Labrador–Quebec border and also include of the East Natashquan River. Furthermore, some is under study to be included in a new park, the Natashquan-Aguanus-Kenamu National Park. The landscape of proposed reserve is deemed to have great beauty, exceptional value, recognized heritage interest, and considerable cultural interest. Therefore, the reserve is meant to protect favourable Atlantic salmon habitats, biodiversity of aquatic and riparian habitats, and old-growth forests. It will also manage sustainable harvesting of fur-bearing animals and develop tourism opportunities, while prohibiting mining, forestry, and hydro-electric development. In May 2015 the Ministry of Forests, Wildlife and Parks of Quebec announced a sport fishing catch-and-release program for large salmon on sixteen of Quebec's 118 salmon rivers. These were the Mitis, Laval, Pigou, Bouleau, aux Rochers, Jupitagon, Magpie, Saint-Jean, Corneille, Piashti, Watshishou, Little Watshishou, Nabisipi, Aguanish and Natashquan rivers. The Quebec Atlantic Salmon Federation said that the measures did not go nearly far enough in protecting salmon for future generations. In view of the rapidly declining Atlantic salmon population catch-and-release should have been implemented on all rivers apart from northern Quebec.