The Richelieu River is a significant waterway located in southern Quebec, Canada. It flows approximately 120 kilometers (75 miles) from Lake Champlain in the United States to the St. Lawrence River. The river serves as a natural border between the United States and Canada for part of its length and is an important route for both transportation and recreation. Historically, the Richelieu River played a crucial role in trade and military movements during the colonial period. Today, it is popular for activities such as boating, fishing, and kayaking, attracting both locals and tourists to its scenic banks and natural beauty.