<P> Mountain men, primarily French, Spanish, and British, roamed the Rocky Mountains from 1720 to 1800 seeking mineral deposits and furs . The fur - trading North West Company established Rocky Mountain House as a trading post in what is now the Rocky Mountain Foothills of present - day Alberta in 1799, and their business rivals the Hudson's Bay Company established Acton House nearby . These posts served as bases for most European activity in the Canadian Rockies in the early 19th century . Among the most notable are the expeditions of David Thompson (explorer), who followed the Columbia River to the Pacific Ocean . On his 1811 expedition, he camped at the junction of the Columbia River and the Snake River and erected a pole and notice claiming the area for the United Kingdom and stating the intention of the North West Company to build a fort at the site . </P> <P> By the Anglo - American Convention of 1818, which established the 49th parallel north as the international boundary west from Lake of the Woods to the "Stony Mountains"; the UK and the USA agreed to what has since been described as "joint occupancy" of lands further west to the Pacific Ocean . Resolution of the territorial and treaty issues, the Oregon dispute, was deferred until a later time . </P> <P> In 1819, Spain ceded their rights north of the 42nd Parallel to the United States, though these rights did not include possession and also included obligations to Britain and Russia concerning their claims in the same region . </P> <P> After 1802, American fur traders and explorers ushered in the first widespread Caucasian presence in the Rockies south of the 49th parallel . The more famous of these include Americans William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith . On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using South Pass in the present State of Wyoming . Similarly, in the wake of Mackenzie's 1793 expedition, fur trading posts were established west of the Northern Rockies in a region of the northern Interior Plateau of British Columbia which came to be known as New Caledonia, beginning with Fort McLeod (today's community of McLeod Lake) and Fort Fraser, but ultimately focused on Stuart Lake Post (today's Fort St. James). </P>

Where do you find great forests in the regions west of the rockies