The Châteauguay River is a river located in southwestern Quebec, Canada. It flows approximately 50 kilometers (31 miles) from its source near Mercier to its confluence with the Saint Lawrence River near Châteauguay. The river is known for its scenic beauty and is a popular spot for recreational activities such as fishing, kayaking, and hiking along its banks. Historically, the Châteauguay River played a significant role in the region's development. It served as a transportation route for Indigenous peoples and later for European settlers. The river's watershed supports diverse ecosystems, making it an important habitat for various species of fish and wildlife.