Alexander Henry 'The Younger' (1765 – 22 May 1814), was an early Canadian fur trader, explorer and diarist. From 1799 until his premature death in 1814 he kept an extensive diary which is the most complete record ever printed of the daily life of a fur trader in the north. These journals cover everything that happened to him in a most matter-of-fact manner and have yielded much material for historians and other researchers of that time period in North American history.
In 1792, with his well-known uncle of the same name, Henry became a partner in the North West Company and he was later a wintering partner of the XY Company and the Pacific Fur Company. His diaries record his travels from Lake Superior to the Pacific Ocean. In Canada, he travelled through Ontario, Manitoba, Assiniboia, Keewatin, Saskatchewan, Alberta and British Columbia. In the United States of America his travels took him through areas that comprise the modern states of Wisconsin, Minnesota, North Dakota, Idaho, Oregon, and Washington. He encountered many different tribes of Indians, and in the north saw much of the Chippewas, the three tribes of the Blackfeet, the Crees, Assiniboines, Sioux, Sarcees, and others. In the south, he reached the Mandans, the Minitari, the Rees, and even the Cheyennes, south of the Missouri River. On the west coast he saw many tribes of the Columbia River, such as the Wanapum. In 1808, he travelled with David Thompson from Lake Winnipeg to Fort Vermilion, Alberta.