Richelieu River at Saint-Marc-sur-Richelieu
|Mouth||St. Lawrence River at Sorel|
|Basin countries||Canada, and appreciable parts of
New York State, Massachusetts, Vermont
|Length||171 km (106 mi)|
|Avg. discharge||330 m3/s (12,000 cu ft/s) at mouth|
|Basin area||23,400 km2 (9,000 sq mi)|
The Richelieu River is a river in Quebec, Canada. It flows from the north end of Lake Champlain about 171 km (106 miles) north, ending at the confluence with the St. Lawrence River at Sorel-Tracy, Quebec downstream and northeast of Montreal. It has a drainage basin of 23,400 square kilometres (9,000 sq mi), of which 19,600 km2 (7,600 sq mi) are in the United States originating in the northeastern faces of the Berkshire Hills and Green Mountains and the eastern slopes of the Adirondack Mountains of New York State and so has a mean discharge of 330 cubic metres per second (12,000 cu ft/s). St. Jean, Chambly, and Sorel are important communities on its route.
The French explorer Samuel de Champlain was the first European to reach the mouth of the river in 1609. Already an important pathway for the Iroquois Indians, it soon became one for French traders as well. They built five forts along its length: Fort Richelieu at its mouth, Fort St. Louis (or Fort Chambly), Fort Ste. Thérese and Fort Saint-Jean (Quebec) on the way, and Fort Ste. Anne on the Isle La Motte, Vermont in Lake Champlain near its source. Some early journals and maps refer to the lower river as the Sorel River. Formerly also called Iroquois River, its French name comes from Fort Richelieu, which in turn was named in memory of Cardinal Richelieu (1585-1642).
The Chambly Canal (9 locks) permits boats to bypass the rapids at St-Jean-sur-Richelieu and Chambly.The Piste cyclable du Canal-de-Chambly is a 20 km (12 mi) bicycle path that follows the towpath along the canal. The bike path is part of Quebec's Route Verte bicycle path network. The canal is a National Historic Site of Canada and is operated by Parks Canada.
The Champlain Canal and Lake Champlain form the U.S. portion of the Lakes to Locks Passage, linking with the Hudson River and allowing navigation using the Richelieu between the St. Lawrence River and New York City and the Erie Canal.