The Mackenzie River, in the Northwest Territories, is 2,635 miles (4,241 km) long, almost 300 miles longer than the Mississippi River in the United States.
It is named for the explorer Alexander Mackenzie, who was the first person to cross Canada and reach the Pacific in 1793.
Alexander Mackenzie traveled the river while trying to reach the Pacific Ocean in 1789.
The large delta of the Mackenzie River provides habitat for migrating Snow Geese, and the estuary is a popular birthing area for Beluga whales.
Three of the world’s 10 largest islands are in Canada: Baffin Island, Ellesmere Island, and Victoria Island.