Mattawa River

Mattawa River Petite Rivière
Pimisi Bay on the Mattawa River
Etymology	Algonquin language
Location
Country	Canada
Province	Ontario
District	Nipissing
Physical characteristics
Source	Trout Lake
• location	North Bay, Ontario
• coordinates	46°18′48″N 79°16′09″W / 46.31333°N 79.26917°W / 46.31333; -79.26917
• elevation	198.5 m (651 ft)
Mouth	Ottawa River
• location	Mattawa, Ontario
• coordinates	46°19′13″N 78°42′26″W / 46.32028°N 78.70722°W / 46.32028; -78.70722
• elevation	148 m (486 ft)
Length	76 km (47 mi)
Basin size	1,170 km2 (450 sq mi)
Basin features
Progression	Ottawa River→ St. Lawrence River→ Gulf of St. Lawrence
River system	Ottawa River drainage basin
Tributaries
• right	Kaibuskong River, Amable du Fond River

The Mattawa River is a river in central Ontario, Canada. It flows east from Trout Lake east of North Bay and enters the Ottawa River at the town of Mattawa. Counting from the head of Trout Lake, it is 76 kilometres (47 mi) long. The river's name comes from the Algonquin word for "meeting of waterways".

Two provincial parks are located along it: the Mattawa River Provincial Park stretches along both sides of the river's banks for almost its full length; and Samuel de Champlain Provincial Park, located about 10 kilometres (6.2 mi) from the river's end.