Alexander Mackenzie reaches the Mackenzie River delta.

Sir Alexander Mackenzie was a Scottish-Canadian explorer and fur trader known for accomplishing the first crossing of North America north of Mexico by a European in 1793. The Mackenzie River and Mount Sir Alexander are named after him.

The Mackenzie River is a river in the Canadian boreal forest and tundra. It forms, along with the Slave, Peace, and Finlay, the longest river system in Canada, the second largest drainage basin of any North American river after the Mississippi.