The Garneau River is a tributary of the Turgeon River flowing in Canada in:

• Cochrane District, Northeastern Ontario;
• Nord-du-Québec, in Jamésie, in the municipality of Eeyou Istchee Baie-James (municipality) in the township of Récher.

The surface of the river is usually frozen from early from November to mid-May, but safe circulation on the ice generally occurs from mid-November to the end of April.

The main watersheds adjacent to the Garneau River are:

• North side: Kaokonimawaga Creek, Detour River, Turgeon River;
• East side: Makwo Creek, Wijinawi Creek, Theo River, Wawagosic River;
• South side: Adimoskadjiwi Creek, Turcotte River, Turgeon River;
• West side: Turcotte River, Little Turcotte River (Ontario).

The Garneau River originates at the mouth of a lake Garneau (length: 0.3 metres (1 ft 0 in); elevation: 286 metres (938 ft)), in Cochrane District, in Ontario.

The mouth of Lake Garneau is located at:

• 2.3 kilometres (1.4 mi) at west of the boundary between Ontario and Quebec;
• 10.1 kilometres (6.3 mi) at southeast of the mouth of the Garneau River;
• 54.9 kilometres (34.1 mi) at south of the mouth of the Turgeon River (in Quebec);
• 66.9 kilometres (41.6 mi) at southeast of a southern bay of Kesagami Lake (in Ontario).

From its source, the Garneau River flows on 22.9 kilometres (14.2 mi) according to the following segments:

• 4.2 kilometres (2.6 mi) southwest by crossing marsh areas to the boundary between Quebec and Ontario;
• 6.5 kilometres (4.0 mi) in Québec including 2.6 kilometres (1.6 mi) to the south-east in the swamp area, then 3.9 kilometres (2.4 mi) to the East, to a stream (coming from the South);
• 12.2 kilometres (7.6 mi) to Nord-East in swamp area, up to the mouth.

The Garneau River flows to the southwest bank of the Turgeon River. This confluence is located at:

• 47.0 kilometres (29.2 mi) at southwest of the mouth of the Turgeon River (confluence with the Harricana River);
• 7.5 kilometres (4.7 mi) at east of the boundary between Quebec and Ontario;
• 84.9 kilometres (52.8 mi) at west of the center of the village of Joutel, Quebec, in Quebec;
• 103 kilometres (64 mi) at north of the city center of La Sarre, Quebec, in Quebec.

The term "Garneau" is a surname of a family of French origin.

The name "rivière Garneau" was officially registered on December 5, 1968, at the Commission de toponymie du Québec, at the creation of this commission.

• Cochrane District, an administrative district of Ontario
• Northeastern Ontario
• Eeyou Istchee Baie-James (municipality)
• Turgeon River, a watercourse
• Harricana River, a watercourse
• James Bay, a body of water
• List of rivers of Ontario
• List of rivers of Quebec