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 southern parts of Quebec and Ontario, in the section of the Great Lakes (bordered entirely by Ontario on the Canadian side) and St. Lawrence basin (often called St. Lawrence Lowlands), is another particularly rich sedimentary plain. Prior to its colonization and heavy urban sprawl of the 20th century, this Eastern Great Lakes lowland forests area was home to large mixed forests covering a mostly flat area of land between the Appalachian Mountains and the Canadian Shield. Most of this forest has been cut down through agriculture and logging operations, but the remaining forests are for the most part heavily protected. In this part of Canada the Gulf of St. Lawrence is one of the world's largest estuary (see Gulf of St. Lawrence lowland forests).