The middle and upper part of the Saint-Michel river valley is served by the Chemin du Nordet; the lower part via Régimbald road and Rexfor road.

The surface of the Saint-Michel river (except the rapids areas) is generally frozen from mid-December to the end of March; safe circulation on the ice is generally done from the end of December to the beginning of March.

The main watersheds adjacent to that of the Saint-Michel river are: The Saint-Michel river rises at the mouth of an unidentified small lake (length: 0.17 kilometres (0.11 mi); altitude: 495 metres (1,624 ft)), located in the municipality of Saint-Donat.

From its source, the Saint-Michel river generally flows northwest in the forest zone over 12.9 kilometres (8.0 mi) according to the following segments: The Saint-Michel river flows at the bottom of a small bay (surrounded by marshes) on the west shore of Lake Archambault in Saint-Donat.

The confluence of the Saint-Michel river is located at: From its confluence, the current of the Saint-Michel river crosses Lake Archambault towards the north on 5.8 kilometres (3.6 mi) passing by the west side of the village of Saint-Donat; then descend successively on 6.3 kilometres (3.9 mi) south-east to Lake Ouareau; on 6.9 kilometres (4.3 mi) first towards the south-east crossing Lake Ouareau to Grande Pointe, then north to the mouth of the lake; on 83.8 kilometres (52.1 mi) following the course of the Ouareau River; on following the course of the L'Assomption River which flows onto the northwest bank of the Saint Lawrence River.