The Nadeau River (in French: rivière Nadeau) is a tributary of the west bank of the Chaudière River which flows northward to empty onto the south bank of the St. Lawrence River.

The main neighboring watersheds of the Nadeau River are: The Nadeau river has its source in the northern part of the municipality of Saint-Séverin, at 8.1 kilometres (5.0 mi) north-west of the center of the village of Tring-Jonction, at 1.4 kilometres (0.87 mi) north-west of the center of the village of Saint-Séverin and at 10.7 kilometres (6.6 mi) west of the Chaudière River.

From its source, the Nadeau River flows over 15.0 kilometres (9.3 mi) divided into the following segments: The Nadeau river empties on the west bank of the Chaudière River, in Vallée-Jonction.

This confluence is located 2.1 kilometres (1.3 mi) downstream of the bridge in the village of Vallée-Jonction, at 8.1 kilometres (5.0 mi) upstream of the Sainte-Marie-de-Beauce and at 4.9 kilometres (3.0 mi) upstream from the confluence of the Savoie River.

The toponym Rivière Nadeau was formalized on December 5, 1968, at the Commission de toponymie du Québec.