Why are the Great Lakes important to Ontario’s geography and economy?

The Great Lakes are vital to Ontario’s geography and economy, serving as both a natural moderator of the environment and a cornerstone of industrial development.

Geographic Importance

The Great Lakes significantly influence Ontario’s climate, particularly in the southern regions. By absorbing heat during warmer months and releasing it during colder periods, the lakes provide a moderating effect that results in cooler summers and warmer winters than would otherwise occur. This influence creates favorable conditions for agriculture, extending the frost-free season in districts near the lakes.12

Economic Importance

• Industry and Trade: The lakes provide an essential transportation route that has historically facilitated the growth of large metropolitan areas and heavy industry, including major steel mills and automobile manufacturing centers.34
• Shipping: The Great Lakes–St. Lawrence River system is a critical international trade route. Infrastructure such as the Welland Canal allows for the movement of bulk commodities like iron ore, coal, and grain, which are vital to the province's steel mills and power plants.53
• Resources: The lakes support commercial and sport fishing, as well as an aquaculture industry. Furthermore, the abundant water supply has been a foundational factor in the development of the province's large-scale industrial base.64