ST. LAWRENCE, a river of North America, forming in its upper reaches part of the N. boundary of the United States, but for the most part confined to the Canadian Dominion. It issues from Lake Ontario at Kingston, where the name begins to be applied to the river, though the remotest source of the highest feeder of its basin, the St. Louis, which enters the W. end of Lake Superior, is in the N. E. of Minnesota. Passing through the chain of Great Lakes on leav ing Lake Ontario, it flows N. E., first through the beautiful district known as the Thousand Isles, from the number of islands large and small (in all about 1, 500), which here vary its course, and then forms the wide expanses called Lakes St. Francis (just after quitting the United States boundary), St. Louis (just above Montreal Island), and St. Peter (a little above Three Rivers, between Montreal and Quebec). Below Quebec it forms a broad estuary, and it enters the Gulf of St. Lawrence by a mouth 26 miles wide, be tween Point des Monts (Saguenay) and the Gaspe Peninsula. • Length from Lake Ontario to the Gulf 760 miles, to the W. point of Anticosti 1,034 miles. The height of Lake Ontario above sea-level is 246.6
feet of which the river descends 206.75 feet in the 348 miles above Montreal. Be low Montreal accordingly, the total fall is about 40 feet, or about 1 foot in 10 miles, a rate presenting no difficulty for navigation; and since the construction of a ship canal, 27% feet deep, through Lake St. Peter, the largest merchant ves sels afloat have been able to reach that city in summer. In the stretches above Montreal the fall of the river-bed takes place in a succession of rapids, to avoid which canals have been constructed. These are in the ascending order the Lachine Canal, miles long, with 5 locks, and a rise of 45 feet; Beauharnois Canal, 11% miles long, with 9 locks, and a rise of 82% feet; Cornwall Canal, 11 miles long, with 6 locks, and a rise of 48 feet; Farran's Point Canal, % miles long, with 1 lock, and a rise of 4 feet; Rapide Plat, 4 miles long, with 2 locks, and a rise of 11% feet; and Galops Canal, 7% miles long, with 3 locks, and a rise of 153! feet. The basin of the St. Lawrence is estimated to contain 297,000 square miles, of which 95,000 are covered with the waters of the Great Lakes.