OTTAWA, the largest tributary of the river St Lawrence; ranking ninth in length among the rivers of Canada, being 685 m. long. It flows first westward to Lake Temiscaming; thence south-east and east. The principal tributaries on the left bank are the Rouge (115 m.), North Nation (60), Lievre (205), Gatineau (240), Coulonge (135), Dumoine (80); and on the right bank, the South Nation (90), Mississippi (105), Madawaska (130) and Petawawa (95). Canals at Ste Anne, Carillon and Grenville permit the passage of vessels drawing 9 ft., from Montreal up to the city of Ottawa. At Ottawa the river is connected with Lake Ontario by the Rideau Canal. The Chaudière Falls, and the Chats and other rapids, prevent continuous navigation above the capital, but small steamers ply on the larger navigable stretches. The Montreal, Ottawa and Georgian Bay Canal is designed to surmount these obstructions and provide a navigable channel from Georgian Bay up French river, through Lake Nipissing and over the height of land to the Ottawa, thence down to Montreal, of sufficient depth to enable vessels drawing 20 or 21 ft. to carry cargo from Chicago, Duluth. Fort William, &c. to Montreal, or, if necessary, to Europe, without breaking bulk. Except the suggested Hudson Bay route, this canal would form the shortest route to the Atlantic seaboard from the great grain-producing areas of western America.
The Ottawa was first explored by Samuel de Champlain in 1613. Champlain describes many of its tributaries, the Chaudière and Rideau Falls, the Long Sault, Chats and other rapids, as well as the character of the river and its banks, with minuteness and reasonable accuracy. He places the Chaudière Falls in 45° 38′, the true position being 45° 27′. The Long Sault Rapids on the Ottawa, about midway between Montreal and the capital, were the scene of one of the noblest exploits in Canadian history, when in 1661 the young Sieur des Ormeaux with sixteen comrades and a handful of Indian allies deliberately gave their lives to save New France from an invasion of the Iroquois. They intercepted the war party at the Long Sault, and for nearly a week held them at bay. When finally the last Frenchman fell under a shower of arrows, the Iroquois were thoroughly disheartened and returned crestfallen to their own country. For a hundred and fifty years thereafter the Ottawa was the great highway from Montreal to the west for explorers and fur-traders. The portage paths around its cataracts and rapids were worn smooth by the moccasined feet of countless voyageurs; and its wooded banks rang with the inimitable chansons of Old Canada, as the canoe brigades swept swiftly up and down its broad stream. Throughout the 19th century the Ottawa was the thoroughfare of the lumbermen, whose immense rafts were carried down from its upper waters to Montreal and Quebec.