The Thompson River is a tributary of the south shore of De Montigny Lake, flowing in the town of Val-d'Or, in the La Vallée-de-l'Or Regional County Municipality, in the administrative region of Abitibi-Témiscamingue, in Quebec, in Canada.

[2] The surface of the Thompson River is generally frozen from mid-December to mid-April.

The neighboring watersheds of the Thompson River are: The source of the Thompson River is located at the mouth of Lemoine Lake (Val-d'Or) which is mainly fed by a strait (from the southwest) connecting it to Mourier Lake.

From its source, the Thompson River flows 4.9 km (3.0 mi) northward forming a navigable strait and collects the waters of the Piché River (coming from the west).

[2] The Thompson River flows on the south shore of Lac De Montigny to: The toponym Thompson river was formalized on December 21, 1982 at the Commission de toponymie du Québec.