American Fur Company (1808-1842) - Founded by John Jacob Astor in 1808, the American Fur Company would become one of the largest businesses in the country at the start of the 19th century. Astor began this ambitious venture to compete with the two great fur-trading companies in Canada - the Hudson's Bay Company and the North West Company. Initially, Astor's operation in the Columbia River Valley of Oregon was under a subsidiary called the Pacific Fur Company and his Great Lakes efforts were under another subsidiary -- the South West Company. However, the War of 1812 destroyed both companies. Five years later, in 1817, Congress passed an act which excluded foreign traders from U.S. territory, making the American Fur Company the biggest in the Great Lakes region. In 1821, the company partnered with the Chouteau interests of St. Louis, Missouri, giving the company a monopoly in the Missouri River region and later, in the Rocky Mountains. Growing larger each year, the American Fur Company made a practice of buying out small businesses or putting them out of business with stiff competition, virtually having a market on the entire fur trade by 1830. Astor withdrew in 1834 and the company split up. To save expenses a number of the many trading posts were closed and heavy competition began to resurface. Shortly, thereafter, the demand for furs began to decrease dramatically. Despite efforts to increase profits by diversifying into other industries like lead mining, the American Fur Company folded in 1842. The remaining assets of the company were split into several smaller operations, most of which failed by the 1850's.

Columbia Fur Company (1821-1827) - When the Hudson's Bay Company merged with the old North West Company in 1821, some 900 employees were dismissed. Many of these men then formed the Columbia Fur Company, which operated between the upper Mississippi and the upper Missouri Rivers. Made up of experienced fur traders, they made impressive profits and soon set up a series of trading posts along the Missouri River. John Jacob Astor, who hated competition, bought out the Columbia Fur Company in July, 1827, giving the American Fur Company a virtual monopoly on the upper Missouri River. Keeping several of the former employees, Astor put Kenneth McKenzie in charge of the new Upper Missouri Outfit of the American Fur Company.

Hudson's Bay Company (1670-present) - Chartered on May 2, 1670, the Hudson's Bay Company (HBC) is the oldest commercial corporation in North America and is one of the oldest in the world. In its early days, it was headquartered in London, England and controlled the fur trade throughout much of British-controlled North America for several centuries. Forging early relationships with a number of Native American tribes, the company's trappers and traders were some of the first European people to set eyes on many locations that would later become the United States and Canada.

The company founded its first headquarters at Fort Nelson at the mouth of the Nelson River in present-day northeastern Manitoba, Canada. Other posts were quickly established around the southern edge of Hudson Bay in Manitoba and present-day Ontario and Quebec.