St. Lawrence River


Region Type Maps & Charts (if available, no international)
North America, New England, Atlantic River St. Lawrence River

744 miles long. One of the principal rivers of N. America. It issues from the NE end of L. Ontario and flows NE, 1st along the U.S.-Can. border, then into S Que., past Montreal and Quebec city, to the Gulf of St. Lawrence, N of Cape Gaspe. It is the outlet of the Great Lakes and together with them forms a c.2,300-mile-waterway from the W end of L. Superior to the Atlantic Ocean. The river is an integral part of the St. Lawrence Seaway (opened 1959). In its upper course the river cuts through a part of the Can. Shield; here, just downstream from L. Ontario, are the Thousand Isls. Below Cornwall, Ont., the river widens into L. St. Francis. Shortly it widens again into L. St. Louis, then descends through the Lachine Rapids to Montreal, head of navigation for very large oceangoing vessels. Bet. Sorel and Trois Rivieres is L. St. Peter. Below the city of Quebec the river is tidal. It gradually increases in width to c.90 miles at its mouth. The river’s principal tributaries are the Richelieu (linking the St. Lawrence with L. Champlain and the Hudson R.), St. Francis, Ottawa, St. Maurice, and Saguenay rivers. The St. Lawrence R. is an important source of hydroelectric power; one of the world’s largest facilities is the Beauharnois power plant near Montreal. Agreements bet. the U.S. and Canada govern power distribution and navigation in the internatl. sect. of the river. Canals have been constructed around the rapids, making the entire river navigable; however, the upper part is unnavigable during the winter months because of ice accumulation. The most important cities and ports along the St. Lawrence are Ogdensburg, N.Y.; Kingston, Brockville, and Cornwall, Ont.; and Montreal, Sorel, Trois Rivieres, Quebec city, and Levis, Que. The many bridges that cross the St. Lawrence R. include the Thousand Isls. Internatl. Bridge (1938), the Roosevelt Internatl. Bridge (1934), and the Seaway Skyway Bridge (1960), all bet. Ont. and N.Y.; the Victoria Bridge (remodeled 1898) at Montreal; and the Quebec Bridge (1917), near Quebec. The St. Lawrence valley is an agr. region; potatoes, grains, hay, vegetables, and dairy cattle are raised.

Sources

Robert A. McCaughey

Related People

Samuel de Champlain

Compiler

Peter Richards