The main hydrographic slopes adjacent to the "West Brock River" are:

• North side: Opataca Lake, Cachisca Lake, Comencho Lake;
• East side: Brock River (Chibougamau River), Chibougamau River, Brock River North, Chibougamau Lake, Barlow River;
• South side: Opémisca Lake, Opémisca River, Chibougamau River;
• West side: Chibougamau River, Mildred River, Omo River, Maicasagi River.

The "West Brock River" originates at the mouth of a small unidentified lake (length: 0.4 kilometres (0.25 mi), altitude: 453 metres (1,486 ft)) in the township of La Rochette, in the Assinica Wildlife Sanctuary. This source is located on the southwestern side of a mountain whose summit reaches 488 metres (1,601 ft) at:

• 46.5 kilometres (28.9 mi) West of Penicouane Bay at south of Mistassini Lake;
• 36.4 kilometres (22.6 mi) Northwest of Opémisca Lake;
• 12.9 kilometres (8.0 mi) North of the mouth of the Brock River West (confluence with the Brock River (Chibougamau River));
• 32.4 kilometres (20.1 mi) North of the mouth of the Brock River (confluence with the Chibougamau River);
• 101.5 kilometres (63.1 mi) Northeast of the mouth of the Chibougamau River (confluence with the Opawica River).
• 153.1 kilometres (95.1 mi) Northeast of the mouth of Goéland Lake (Waswanipi River);
• 54.1 kilometres (33.6 mi) Northwest of the village center of Chapais;
• 54.4 kilometres (33.8 mi) Northwest of downtown Chibougamau;
• 305.8 kilometres (190.0 mi) East of the mouth of the Nottaway River.

From its source, the "Brock River West" flows over 28.9 kilometres (18.0 mi) according to the following segments:

• 19.3 kilometres (12.0 mi) South, southwest to a small lake, then South, to a dump (coming from the west) of a group of lakes;
• 2.5 kilometres (1.6 mi) to the South, then to the East at the end of the segment, to the discharge (coming from the West) of two lakes;
• 7.1 kilometres (4.4 mi) East, then South, to its mouth.[2]

The "West Brock River" flows into the North bank of the Brock River (Chibougamau River) into a river bend, downstream of a series of falls and rapids. From there, the current descends towards the South-West by borrowing the Brock River (Chibougamau River). From the mouth of the river, the current flows to the Southwest through the Chibougamau River, then through Waswanipi River to the East shore of Goéland Lake (Waswanipi River). The latter is crossed to the northwest by the Waswanipi River which is a tributary of Matagami Lake.

The mouth of the "West Brock River" located at:

• 18.8 kilometres (11.7 mi) North of the mouth of the Brock River (Chibougamau River);
• 89.6 kilometres (55.7 mi) Northeast of the mouth of the Chibougamau River (confluence with the Opawica River);
• 144.5 kilometres (89.8 mi) Northeast of the mouth of Goéland Lake (Waswanipi River);
• 29.0 kilometres (18.0 mi) Northwest of the village center of Chapais;
• 50.8 kilometres (31.6 mi) Northwest of downtown Chibougamau.

• James Bay
• Rupert Bay
• Nottaway River, a watercourse
• Matagami Lake, a body of water
• Waswanipi River, a watercourse
• Goéland Lake (Waswanipi River), a body of water
• Lake Waswanipi, a body of water
• Chibougamau River, a watercourse
• Brock River (Chibougamau River), a watercourse
• Assinica Wildlife Sanctuary
• List of rivers of Quebec