The Ottawa-Bonnechere Graben measures about 700 km (435 mi), running from the Montreal area on the east to near Sudbury See more

The depressions formed by the graben across the rugged Canadian Shield were a spillway for the Great Lakes after the last ice age. Later they became a thoroughfare for exploration and … See more

• Welcome to the Ottawa Valley, a Canadian Geographic article about the valley
• Ottawa River article at Great Canadian Rivers
• Preview of the Canadian Geographic article, … See more

Since the Late Proterozoic to Early Paleozoic, erosion has removed the volcanic peaks, exposing a number of relic volcanic pipes, such as Callander Bay and the See more

• Midcontinent Rift System – Geological rift in the center of the North American continent
• Ottawa Valley – Valley in Ontario and Quebec in Canada
• Volcanology of Canada – Volcanic activity in Canada See more