Lake Winnipeg, << WIHN uh `pehg,` >> in south-central Manitoba, is the third largest lake lying entirely within Canada. Only Great Bear Lake and Great Slave Lake in the Northwest Territories are larger. Lake Winnipeg covers 9,416 square miles (24,387 square kilometers), and is known as one of the “Great Lakes of Manitoba” (see Manitoba (Rivers and lakes) ). The lake is 258 miles (416 kilometers) long, and from 20 to 60 miles (32 to 97 kilometers) wide. Lake Winnipeg does not exceed 70 feet (21 meters) in depth.
In ancient times, Lake Winnipeg and its two large neighbors–Lakes Winnipegosis and Manitoba–formed parts of large, shallow Lake Agassiz. Lake Agassiz was created by glaciers during the most recent ice age, which ended about 11,500 years ago (see Lake Agassiz ). Large islands in Lake Winnipeg include Reindeer Island and Hecla Island. The lake’s fisheries are the most important in Manitoba. Lake Winnipeg is a storage reservoir for a river system that includes the Saskatchewan, Nelson, Red, and Winnipeg rivers.