Saint-Cyr River (Ottawa River tributary)

The Saint-Cyr River is a tributary of the eastern shore of the Ottawa River. The Saint-Cyr River flows into the Municipality Rapides-des-Joachims, then from Sheenboro into the Regional County Municipality (MRC) Pontiac Regional County Municipality, in Outaouais administrative region, in Quebec, in Canada.

Geography
• The hydrographic slopes adjacent to the Saint-Cyr River are:

• north side: Poussière River, Dontenwill Lake, Bronson Lake;

• east side: Boom River, Marie-Jeanne Creek;

• south side: Ottawa River;

• west side: Penniseault Creek.

• "Lac la Truite" (English: Troot Lake) (length: 2.4 km, altitude: 355 m) is the headwaters of the Saint-Cyr River.

• From "Lac la Truite", the Saint-Cyr River flows over:

• 2.6 km to the southwest, to the outlet (coming from the north-west) of Fontaine Lake (altitude: 314 m);

• 2.0 km southerly to the outlet (from the east) of Nuage Lake (elevation: 312 m);

• 3.3 km to the southwest, to the outlet (coming from the west) of Braun Lake (altitude: 300 m);

• 2.2 km southerly to the Bory Lake outlet (from the northwest) (elevation 288 m);

• 360 m to the south, to the mouth of the outlet (coming from the southeast) of Lac Sérien (altitude: 267 m;

• 2.5 km to the southwest, to the outlet (coming from the north) of Bonpland Lake (altitude: 301 m);

• 2.3 km southerly to the north shore of Aberdeen Lake;

• 1.2 km crossing Aberdeen Lake to the south (length: 0.4 km, altitude: 212 m);

• 5.0 km to the south, to the mouth of the Boom river (coming from the north) which in particular drains the "Lac de la Touche" (altitude: 168 m);

• 1.0 km southeast across rapids to the outlet (from the north-east) of Walls Lake (elevation 190 m) and Lac des Amis (elevation 274 m);

• 2.6 km (or 1.4 km direct line) southerly passing west of the James Little Little Ecological Reserve and zigzagging to the mouth.

• The Saint-Cyr River is a tributary of the northeastern shore of the Ottawa River. The mouth of the Saint-Cyr River is located almost opposite the mouth of "Tee Creek" (Tee Creek - Ontario), 4.1 km downstream of Rapides-des-Joachims, Quebec and 1.1 km downstream of "Point Stewart" (Ontario).

Toponymy
The former name of the river was "Boom West Brook", as opposed to the branch being referred to as "Boom Creek" in this hydrographic slope.

The toponym "Saint-Cyr River" was formalized on December 5, 1968, at the Commission de toponymie du Québec.