Lake McConnell was a very large proglacial lake that existed in what is now Canada from 11,800 to 8,300 years ago.[1] Other sources give starting and ending dates of about 12,000[2] and between 9,000 and 8,000 years ago,[3] respectively. It covered parts of what are now the Great Bear Lake, Great Slave Lake and Lake Athabaska basins up to an elevation of 280m (920feet)[4] or 305m (1,001feet),[5] with a maximum surface area of 210000km2 achieved 10,500 years ago.[1] At its greatest length of 1100km (700miles), it was longer than any modern freshwater lake.[2] "Lake McConnell (or its smaller predecessor, Lake Peace) is believed to have drained first into Lake Agassiz", an even larger lake to the southeast, "then into the Arctic Ocean via the Mackenzie River, then back into Lake Agassiz, and then back to the Arctic Ocean" at various times in its history.[2] Between 9,000 and 8,000 years ago, it divided to form Great Slave Lake and Lake Athabasca. These two and Great Bear Lake are considered its 'daughter' lakes.[2]
