Lake Agassiz

Lake Agassiz, ancient North American lake that covered much of what is now the Canadian province of Manitoba and parts of other provinces and the United States. It was formed by melting glaciers during the last ice age. Lake Agassiz was the largest of the glacial lakes, reaching its maximum size (approximately 135,000 sq mi/350,000 sq km) between 7900 and 7500 B.C. The continued runoff from the glaciers caused the lake to drain into the Hudson Bay, except for the deeper areas that became smaller lakes such as Manitoba, Winnipeg, and Winnipegosis.