What is the longest river in Canada?

The Mackenzie river is the longest river in Canada. The Mackenzie is 4,241 km/2,635 mi long. It is both the largest and longest river system in Canada, and is exceeded only by the Mississippi River system in North America. It flows through a vast, isolated region of forest and tundra entirely within the country's Yukon and Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories. The river's mainstem runs 1,738 kilometres (1,080 mi) in a northerly direction to the Arctic Ocean, draining a vast area nearly the size of Indonesia. It is the largest river flowing into the Arctic from North America, and with its tributaries is one of the longest rivers in the world.

The Mackenzie River was named after Scottish explorer Alexander Mackenzie, who travelled the river in the hope it would lead to the Pacific Ocean, but instead reached the Arctic Ocean on 14 July 1789. No European reached its mouth again until Sir John Franklin on 16 August 1825. The following year he traced the coast west until blocked by ice while John Richardson followed the coast east to the Coppermine River. In 1849 William Pullen reached the Mackenzie from the Bering Strait.

The Royal Canadian Mint honoured the 200th anniversary of the naming of the Mackenzie River with the issue of a silver commemorative dollar in 1989.