Columbia River in the context of "Mount Jefferson (Bitterroot Range)"

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.

Columbia (/kəˈlʌmbiə/; kə-LUM-bee-ə), also known as Lady Columbia or Miss Columbia, is a female national personification of the United States. It was also a historical name applied to the Americas and to the New World. The association has given rise to the names of many American places, objects, institutions and companies, including the District of Columbia; Columbia, South Carolina; Columbia University; "Hail, Columbia"; Columbia Rediviva; and the Columbia River. Images of the Statue of Liberty (Liberty Enlightening the World, erected in 1886) largely displaced personified Columbia as the female symbol of the United States by around 1920, and Lady Liberty was seen as both an aspect of Columbia and a rendition of the Goddess of Liberty. She is the central element of the logo of Hollywood film studio Columbia Pictures.

Columbia is a Neo-Latin toponym, used since the 1730s to refer to the Thirteen Colonies that would form the United States. It originated from the name of the Genoese explorer Christopher Columbus and from the Latin ending -ia, common in the Latin names of countries (paralleling Britannia, Gallia, Zealandia, and others).

Oregon (/ˈɒrɪɡən, -ɡɒn/ ORR-ih-ghən, -⁠gon) is a state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. The 42° north parallel delineates the southern boundary with California and Nevada. The western boundary is formed by the Pacific Ocean.

Oregon has been home to many indigenous nations for thousands of years. The first European traders, explorers, and settlers began exploring what is now Oregon's Pacific coast in the early to mid-16th century. As early as 1564, the Spanish began sending vessels northeast from the Philippines, riding the Kuroshio Current in a sweeping circular route across the northern part of the Pacific. In 1592, Juan de Fuca undertook detailed mapping and studies of ocean currents in the Pacific Northwest, including the Oregon coast as well as the strait now bearing his name. The Lewis and Clark Expedition traversed Oregon in the early 19th century, and the first permanent European settlements in Oregon were established soon afterward by trappers and fur traders. The United States received joint occupation rights to the region from the United Kingdom through the Treaty of 1818. The Oregon Treaty of 1846 formally brought Oregon under American sovereignty, and the Oregon Territory was created two years later. Oregon was admitted to the United States on February 14, 1859, becoming the 33rd state.

Windsurfing is a wind-propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the Californian aerospace and surf culture. Windsurfing gained a popular following across Europe and North America by the late 1970s and had achieved significant global popularity by the 1980s. Windsurfing became an Olympic sport in 1984.

Grand Coulee Dam is a concrete gravity dam on the Columbia River in the U.S. state of Washington, built to produce hydroelectric power and provide irrigation water. Constructed between 1933 and 1942, Grand Coulee originally had two powerhouses. The third powerhouse ("Nat"), completed in 1974 to increase energy production, makes Grand Coulee the largest power station in the United States by nameplate capacity at 6,809 MW.

The proposal to build the dam was the focus of a bitter debate during the 1920s between two groups. One group wanted to irrigate the ancient Grand Coulee with a gravity canal while the other pursued a high dam and pumping scheme. The dam supporters won in 1933, but, although they fully intended otherwise, the initial proposal by the Bureau of Reclamation was for a "low dam" 290 feet (88 m) tall which would generate electricity without supporting irrigation. That year, the U.S. Bureau of Reclamation and a consortium of three companies called MWAK (Mason-Walsh-Atkinson Kier Company) began construction on a high dam, although they had received approval for a low dam. After visiting the construction site in August 1934, President Franklin Delano Roosevelt endorsed the "high dam" design, which at 550 ft (168 m) high would provide enough electricity to pump water into the Columbia basin for irrigation. Congress approved the high dam in 1935, and it was completed in 1942. The first waters overtopped Grand Coulee's spillway on June 1 of that year.

In March 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, Washington, United States. A series of phreatic blasts occurred from the summit and escalated for nearly two months until a catastrophic, major explosive eruption took place on May 18, 1980, at 8:32 a.m. The eruption, which had a volcanic explosivity index of 5, was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California. It has often been considered the most disastrous volcanic eruption in U.S. history.

The eruption was preceded by a series of earthquakes and steam-venting episodes caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope. An earthquake at 8:32:11 am PDT (UTC−7) on May 18, 1980, caused the entire weakened north face to slide away, a sector collapse which was the largest subaerial landslide in recorded history. This allowed the partly molten rock, rich in high-pressure gas and steam, to suddenly explode northward toward Spirit Lake in a hot mix of lava and pulverized older rock, overtaking the landslide. An eruption column rose 80,000 feet (24 km; 15 mi) into the atmosphere and deposited ash in eleven U.S. states and various Canadian provinces. At the same time, snow, ice, and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 miles (80 km; 260,000 ft) to the southwest. Less severe outbursts continued into the next day, only to be followed by other large, but not as destructive, eruptions later that year. The thermal energy released during the eruption was equal to 26 megatons of TNT.

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.

Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency (IAEA) definition).

Such contamination presents a hazard because the radioactive decay of the contaminants produces ionizing radiation (namely alpha, beta, gamma rays and free neutrons). The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable.

Johnson Creek is a 25-mile (40 km) tributary of the Willamette River in the Portland metropolitan area of the U.S. state of Oregon. Part of the drainage basin of the Columbia River, its catchment consists of 54 square miles (140 km) of mostly urban land occupied by about 180,000 people as of 2012. Passing through the cities of Gresham, Portland, and Milwaukie, the creek flows generally west from the foothills of the Cascade Range through sediments deposited by glacial floods on a substrate of basalt. Though polluted, it is free-flowing along its main stem and provides habitat for salmon and other migrating fish.

Prior to European settlement, the watershed was heavily forested and was used by Native Americans of the Chinook band for fishing and hunting. In the 19th century, non-Native American settlers cleared much of the land for farming, and the stream is named for one of these newcomers, William Johnson, who in 1846 built a water-powered sawmill along the creek. By the early 20th century, a rail line parallel to the stream encouraged further residential and commercial development. As urban density increased in the floodplain, seasonal floods grew more damaging. In the 1930s the Works Progress Administration of the federal government lined the lower 15 miles (24 km) of Johnson Creek with rock to control the floods. Despite this, the creek flooded 37 times between 1941 and 2006. Since the 1990s, regional planners have tried to reduce flooding by controlling stormwater runoff, creating stream meanders, reducing erosion, replacing impervious surfaces, and protecting riparian buffers.

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.