Major Mountains, Lakes, Rivers, and Hills of Ontario

Ontario’s vast geography includes ancient shields, Great Lakes shorelines, powerful rivers, and rolling highlands.

Mountains & Highlands

• Canadian Shield: Covers most of northern/central Ontario; ancient bedrock with rugged hills, ridges, and thousands of lakes.
• Niagara Escarpment: UNESCO Biosphere Reserve; dramatic limestone cliff running along southwestern Ontario, offering cliffs, waterfalls, and vistas.

Major Lakes

• Lake Superior: World’s largest freshwater lake by surface area; shared with Michigan.
• Lake Huron: Second-largest in Ontario; famous for Georgian Bay and Manitoulin Island.
• Lake Simcoe: Central Ontario; popular for recreation, ice fishing, and islands.
• Lake of the Woods: Straddles Ontario–Minnesota border; 14,000+ islands, world-class fishing.

Major Rivers

• St. Lawrence River: Forms part of Ontario–New York border; vital shipping and hydroelectric corridor.
• Ottawa River: Eastern border; whitewater rafting, scenic valleys.
• Niagara River: Connects Lake Erie to Lake Ontario; includes Niagara Falls.

Notable Hills & Uplands

• Blue Mountains: Southwest; skiing, hiking, apple orchards.
• Caledon Hills: Near Toronto; rolling terrain, conservation areas.
• Norfolk Sand Hills: Southwest; unique dunes, wetlands, Carolinian forest.
• Haliburton Highlands: Central; rugged cottage country with lakes, forests, and trails.

These features make Ontario a haven for outdoor recreation and ecological diversity.