Ottawa River drainage basin
The Ottawa River drainage basin is the drainage basin in northern North America where surface water empties into the Ottawa River and adjoining waters. Spanning an area of about , it is the 12th largest drainage basin in Canada, occupying the Canadian provinces of Ontario and Quebec. It accounts for about 11% of the total Saint Lawrence River drainage area.
Geography of Canada
The Canadian Rockies are part of a major continental divide that extends north and south through western North America and western South America. The Columbia and the Fraser Rivers have their headwaters in the Canadian Rockies and are the second and third largest rivers respectively to drain to the west coast of North America. To the west of their headwaters, across the Rocky Mountain Trench, is a second belt of mountains, the Columbia Mountains, comprising the Selkirk, Purcell, Monashee and Cariboo Mountains sub-ranges.