Lake Winnipeg: Manitoba's Inland Sea

Lake Winnipeg lies entirely within the Canadian province of Manitoba. It's the world's 10th-largest freshwater lake by surface area (24,514 km² / 9,465 mi²) and the largest lake wholly within Canada (Great Lakes are shared with the U.S.).

Key Facts

• Dimensions: 416 km (258 mi) long × up to 109 km (68 mi) wide.
• Depth: Average 12 m (39 ft); max 36 m (118 ft) — relatively shallow.
• Drainage: Northward via Nelson River → Hudson Bay (part of Arctic watershed).
• Major Inflows: Saskatchewan River (largest), Winnipeg River, Red River, Dauphin River.
• Islands: 100+ (Hecla, Black, Deer, Berens — Hecla is a provincial park).

Ecological & Economic Importance

• Fishery: Commercial (walleye, sauger, whitefish, lake trout) + recreational.
• Hydroelectric: Churchill River Diversion regulates outflow for Nelson River dams (Kettle, Long Spruce, Limestone).
• Transport: Seasonal ferry/barge service to northern communities.
• Recreation: Beaches (Grand Beach Provincial Park), boating, ice fishing.
• Indigenous Homelands: Anishinaabe, Cree, Métis communities with treaty rights.

Environmental Concerns

• Algal blooms (phosphorus from agriculture/sewage).
• Water level regulation impacts (shoreline erosion, wetland loss).
• Invasive species (zebra mussels detected 2013).
• Climate change (warming, altered ice cover).

Lake Winnipeg is Manitoba's defining geographic feature—a vast, shallow, life-rich inland sea at the heart of the province.