Continental Divide of the Americas in the context of "Great Divide Basin"

Oregon Country was a large region of the Pacific Northwest of North America that was subject to a long dispute between the United Kingdom and the United States in the early 19th century. The area, which had been demarcated by the Treaty of 1818, consisted of the land north of 42° N latitude, south of 54°40′ N latitude, and west of the Rocky Mountains down to the Pacific Ocean and east to the Continental Divide. Article III of the 1818 treaty gave joint control to both nations for ten years, allowed land to be claimed, and guaranteed free navigation to all mercantile trade. However, both countries disputed the terms of the international treaty. Oregon Country was the American name, while the British used Columbia District for the region.

British and French Canadian fur traders had entered Oregon Country prior to 1810 before the arrival of American settlers from the mid-1830s onwards, which led to the foundation of the Provisional Government of Oregon. Its coastal areas north of the Columbia River were frequented by ships from all nations engaged in the maritime fur trade, with many vessels between the 1790s and 1810s coming from Boston. The Hudson's Bay Company, whose Columbia Department comprised most of the Oregon Country and north into New Caledonia and beyond 54°40′ N, with operations reaching tributaries of the Yukon River, managed and represented British interests in the region.

The Centennial Mountains are the southernmost sub-range of the Bitterroot Range in the U.S. states of Idaho and Montana. The Centennial Mountains include the Western and Eastern Centennial Mountains. The range extends east from Monida Pass along the Continental Divide to Henrys Fork 48 km (30 mi) NNW of Ashton, Idaho; bounded on the west by Beaver Creek, on the north by Centennial Valley and Henrys Lake Mountains, on the east by Henrys Lake Flat, and on the south by Shotgun Valley and the Snake River Plain. The highest peak in the range is Mount Jefferson.

They are one of only a few ranges within the Rocky Mountains that trend west to east, and the Continental Divide runs along their ridge line.

The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select group of U.S. Army and civilian volunteers under the command of Captain Meriwether Lewis and his close friend Second Lieutenant William Clark. Clark, along with 30 others, set out from Camp Dubois (Camp Wood), Illinois, on May 14, 1804, met Lewis and ten other members of the group in St. Charles, Missouri, then went up the Missouri River. The expedition crossed the Continental Divide of the Americas near the Lemhi Pass, eventually coming to the Columbia River, and the Pacific Ocean in 1805. The return voyage began on March 23, 1806, at Fort Clatsop, Oregon, ending six months later on September 23 of that year.

President Thomas Jefferson commissioned the expedition, shortly after the Louisiana Purchase of 1803, to explore and detail as much of the new territory as possible. Furthermore, he wished to find a practical travel route across the western half of the continent—directly avoiding the hot and desolate desert southwest—and to establish an American presence in the new lands before European powers attempted to establish claims of their own. The campaign's secondary objectives were scientific, economical and humanitarian, i.e., to document the West's biodiversity, topography and geography and to establish positive trade relations with (potentially unknown) Native American tribes. The expedition returned to St. Louis to report their findings to President Jefferson via maps, sketches, and various journals.

The Pacific Slope describes geographic regions in North American, Central American, and South American countries that are west of the continental divide and slope down to the Pacific Ocean. In North America, the Rocky Mountains mark the eastern border of the Pacific Slope. In Central and South America, the region is much narrower, confined by the Sierra Madre Occidental in Central America, and by the Andes in South America. The phrase is still used today mostly for scientific purposes to refer to regions inhabited by specific species.

It was and is still occasionally used to describe the region in North America during the 19th century and the expansion of the Old West. It includes the states and territories west of the continental divide that runs down the Rocky Mountains in North America. This included the territories and the states that emerged from them, including California, Oregon Territory, Washington Territory, Nevada Territory, Idaho Territory, Colorado Territory, and Utah Territory. The region is drained by the Columbia, Sacramento, San Joaquin and Colorado River systems. In the United States, the Pacific-slope flycatcher takes its name from the region it inhabits.

The Oregon boundary dispute or the Oregon Question was a 19th-century territorial dispute over the political division of the Pacific Northwest of North America between several nations that had competing territorial and commercial aspirations in the region.

Expansionist competition into the region began in the 18th century, with participants including the Russian Empire, Great Britain, Spain, and the United States. After the War of 1812, the Oregon dispute took on increased importance for diplomatic relations between the British Empire and the fledgling American republic. In the mid-1820s, the Russians signed the Russo-American Treaty of 1824 and the Russo-British Treaty of 1825, and the Spanish signed the Adams–Onís Treaty of 1819, by which Russia and Spain formally withdrew their respective territorial claims in the region, and the British and the Americans acquired residual territorial rights in the disputed area. But the question of sovereignty over a portion of the North American Pacific coast was still contested between the United Kingdom and the United States. The disputed area was defined as the region west of the Continental Divide of the Americas, north of Mexico's Alta California border of 42nd parallel north, and south of Russian America at parallel 54°40′ north. The British generally called this region the Columbia District and the Americans generally called it Oregon Country.

The Convention respecting fisheries, boundary and the restoration of slaves, also known as the London Convention, Anglo-American Convention of 1818, Convention of 1818, or simply the Treaty of 1818, is an international treaty signed in 1818 between the United States and the United Kingdom. This treaty resolved standing boundary issues between the two nations. The treaty allowed for joint occupation and settlement of the Oregon Country, known to the British and in Canadian history as the Columbia District of the Hudson's Bay Company, and including the southern portion of its sister district New Caledonia.

The two nations agreed to a boundary line involving the 49th parallel north, in part because a straight-line boundary would be easier to survey than the pre-existing boundaries based on watersheds. The treaty marked both the United Kingdom's last permanent major loss of territory in what is now the Continental United States and the United States' first permanent significant cession of North American territory to a foreign power, the second being the Webster–Ashburton Treaty of 1842. The British ceded all of Rupert's Land south of the 49th parallel and east of the Continental Divide, including all of the Red River Colony south of that latitude, while the United States ceded the northernmost edge of the Missouri Territory north of the 49th parallel.

The North-Western Territory was a region of British North America extant until 1870 and named for where it lay in relation to Rupert's Land.

Because of the lack of development, exploration, and cartographic limits of the time, the exact boundaries, ownership, and administration of the region were not precisely defined when the territory was extant. There is also not a definitive date when the British first asserted sovereignty over the territory. Maps vary in defining the boundaries of the territory; however, in modern usage, the region is generally accepted to be the region bounded by modern-day British Columbia, the continental divide with Rupert's Land, Russian America (later Alaska), and the Arctic Ocean. The territory covered what is now the Yukon, mainland Northwest Territories, northwestern mainland Nunavut, northwestern Saskatchewan, and northern Alberta.

Butte (/bjuːt/ BYEWT) is a consolidated city-county in and the county seat of Silver Bow County, Montana, United States. In 1977, the city and county governments consolidated to form the sole entity of Butte-Silver Bow. The city covers 718 square miles (1,860 km), and, according to the 2020 census, has a population of 34,494, making it Montana's fifth-largest city. It is served by Bert Mooney Airport with airport code BTM.

Established in 1864 as a mining camp in the northern Rocky Mountains on the Continental Divide, Butte experienced rapid development in the late 19th century, and was Montana's first major industrial city. In its heyday between the late 19th and early 20th centuries, it was one of the largest copper boom towns in the American West. Employment opportunities in the mines attracted surges of European and Asian immigrants, particularly the Irish; as of 2017, Butte has the largest population of Irish Americans per capita of any U.S. city.