Born Stornoway (Steòrnabhagh), Isle of Lewis, Scotland Died: March 12, 1820 Genre: Travel, Geography, Exploration Sir Alexander Mackenzie (or MacKenzie) also known as Alasdair MacCoinnich (1764 - 12 March 1820) was a Scottish explorer. He is known for accomplishing the first east to west crossing of North America north of Mexico, which preceded the more famous Lewis and Clark Expedition by 12 years. His overland crossing of what is now Canada reached the Pacific Ocean in 1793. The Mackenzie River, the longest river system in Canada and the second longest in North America, is named after him. Librarian note: There are more authors with this name. Go to Alexander Mackenzie (1838 - 1898) for the Scottish author and historian. Less