The lower portion of the "West Brock River" hydrographic slope is accessible by a few forest roads from the south where route 113 connects Lebel-sur-Quévillon to Chibougamau.

The surface of the "West Brock River" is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

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.

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: This hydronym evokes the memory of Reginald W. Brock, who, at the end of the 1896 geological exploration campaign, was assistant to Dr. Robert Bell of the Geological Survey of Canada, made a rapid geological reconnaissance of the road between the lakes Waswanipi Lake and Mistassini through the rivers Waswanipi, Chibougamau and Barlow and the Lake Waskonichi.