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Oregon is a state in the Pacific Northwest region of the United States of America, bordering the Pacific Ocean, California, Washington, Idaho, and Nevada. Its northern border lies along the Columbia River and the eastern border lies along the Snake River. Two north-south mountain ranges—the Pacific Coast Range and the Cascade Mountain Range—form the two boundaries of the Willamette Valley, one of the most fertile and agriculturally productive regions in the world.
Oregon has one of the most diverse landscapes of any state in the US. It is well known for its tall, dense forests and its accessible, scenic Pacific coastline. Other areas include the semiarid scrublands, prairies, and deserts that cover approximately half the state in eastern and north-central Oregon. It is one of the few places in the Northern Hemisphere where lift-serviced alpine skiing is available year round.
Oregon's population in 2000 was 3,421,399, a 20.4% increase over 1990. The Census Bureau estimated Oregon's population to have reached 3,594,586 by 2004.
Geography
Oregon's geography may be split roughly into six areas:
The Coast Range
The Pacific Coast Ranges are the series of mountain ranges that stretch along west coast of North America from Alaska to northern and central Mexico. They are also known as the Pacific Cordillera, especially in Canada where this term also includes the Rockies and Columbia Mountains and others. The character of the ranges varies considerably, from the record-setting tidewater glaciers in the ranges of Alaska, to the low but rugged and scrub-covered hills of southern California, but the entire coast is consistent in dropping steeply into the sea, often resulting in photogenic views. Along the British Columbia and Alaska coast, the mountains intermix with the sea in a complex maze of fjords, with thousands of islands.
There are a handful of small coastal plains at the mouths of rivers that have punched through the mountains, most notably at the Copper River in Alaska, the Fraser River in British Columbia, the Columbia River between Washington and Oregon, and the Sacramento River in California, the last creating San Francisco Bay.
From the vicinity of San Francisco Bay north, it is common in winter for cool unstable air masses from the Gulf of Alaska to make landfall in one of the Coast Ranges, resulting in heavy precipitation, both as rain and snow, especially on their western slopes.
The Willamette Valley
The Willamette Valley is the region that surrounds the Willamette River as it proceeds northward from its emergence from mountains near Eugene to its confluence with the Columbia River at Portland. One of the most productive agricultural areas of the world, the valley was the destination of choice for the emigrants on the Oregon Trail in the 1840s. It has formed the cultural and political heart of Oregon since the days of the Oregon Territory, and is home to 70% of Oregon's population.
The Cascade Mountains
The Cascade Range is a mountainous region famous for its chain of tall volcanoes called the High Cascades that run north-south along the west coast of North America from British Columbia through Washington and Oregon to the Shasta Cascade area of northern California. The small part of the range in British Columbia is called the Cascade Mountains or Canadian Cascades; the former term is also sometimes used by Washington residents to refer to the Washington section of the Cascades.
The Cascades are part of the Pacific Ring of Fire, the ring of volcanoes around the Pacific Ocean. All of the known historic eruptions in the contiguous United States have been from Cascade volcanoes. The two most recent were Lassen Peak in 1914 to 1921 and a major eruption of Mount St. Helens in 1980. Minor eruptions of Mount St. Helens have also occurred, most recently in 2005.
The Klamath Mountains
The Klamath Mountains are a mountain range in northwest California and southwest Oregon, the highest peaks being Mount Eddy (2744m / 9002') in Trinity County, California, and Mount Ashland (2296m / 7533') in Jackson County, Oregon. They have a varied geology, with substantial areas of serpentine and marble, and a climate characterised by cold winters with very heavy snowfall, and warm summers with limited rainfall. As a consequence of the geology, they have a unique flora, known as the Klamath-Siskiyou forests, which includes several endemic or near-endemic trees, such as Port Orford-cypress (Chamaecyparis lawsoniana), Foxtail pine (Pinus balfouriana spp, balfourinana), Brewer spruce (Picea breweriana) and Kalmiopsis (Kalmiopsis leachiana), forming one of the largest collections of different conifers in the world. The northernmost range of the Klamath Mountains are known as the Siskiyou Mountains.
The Columbia River Plateau
The Columbia River Plateau lies across parts of the states of Washington, Oregon, and Idaho. During late Miocene and early Pliocene times, one of the largest flood basalts ever to appear on the earth's surface engulfed about 63,000 square miles (160,000 km˛) of the Pacific Northwest, forming a large igneous province. Over a period of perhaps 10 to 15 million years lava flow after lava flow poured out, eventually accumulating to a thickness of more than 6,000 feet (1.8 km). As the molten rock came to the surface, the earth's crust gradually sank into the space left by the rising lava. The subsidence of the crust produced a large, slightly depressed lava plain now known as the Columbia Basin or Plateau. The ancient Columbia River was forced into its present course by the northwesterly advancing lava. The lava, as it flowed over the area, first filled the stream valleys, forming dams that in turn caused impoundments or lakes. In these ancient lake beds are found fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals.
The Basin and Range Region
The Great Basin is a large, arid region of the western United States of America, commonly defined as the contiguous watershed region, roughly between the Rocky Mountains and the Sierra Nevada, that has no natural outlet to the sea. The Great Basin Desert is defined by the extent of characteristic plant species, and covers a somewhat different area. The Great Basin Culture Area, home to the Great Basin tribes also extends further to the north and east than the hydrographic basin.
Oregon has one of the most diverse landscapes of any state in the US. It is well known for its tall, dense forests and its accessible, scenic Pacific coastline. Other areas include the semiarid scrublands, prairies, and deserts that cover approximately half the state in eastern and north-central Oregon. It is one of the few places in the Northern Hemisphere where lift-serviced alpine skiing is available year round.
Oregon's population in 2000 was 3,421,399, a 20.4% increase over 1990. The Census Bureau estimated Oregon's population to have reached 3,594,586 by 2004.
Geography
Oregon's geography may be split roughly into six areas:
The Coast Range
The Pacific Coast Ranges are the series of mountain ranges that stretch along west coast of North America from Alaska to northern and central Mexico. They are also known as the Pacific Cordillera, especially in Canada where this term also includes the Rockies and Columbia Mountains and others. The character of the ranges varies considerably, from the record-setting tidewater glaciers in the ranges of Alaska, to the low but rugged and scrub-covered hills of southern California, but the entire coast is consistent in dropping steeply into the sea, often resulting in photogenic views. Along the British Columbia and Alaska coast, the mountains intermix with the sea in a complex maze of fjords, with thousands of islands.
There are a handful of small coastal plains at the mouths of rivers that have punched through the mountains, most notably at the Copper River in Alaska, the Fraser River in British Columbia, the Columbia River between Washington and Oregon, and the Sacramento River in California, the last creating San Francisco Bay.
From the vicinity of San Francisco Bay north, it is common in winter for cool unstable air masses from the Gulf of Alaska to make landfall in one of the Coast Ranges, resulting in heavy precipitation, both as rain and snow, especially on their western slopes.
The Willamette Valley
The Willamette Valley is the region that surrounds the Willamette River as it proceeds northward from its emergence from mountains near Eugene to its confluence with the Columbia River at Portland. One of the most productive agricultural areas of the world, the valley was the destination of choice for the emigrants on the Oregon Trail in the 1840s. It has formed the cultural and political heart of Oregon since the days of the Oregon Territory, and is home to 70% of Oregon's population.
The Cascade Mountains
The Cascade Range is a mountainous region famous for its chain of tall volcanoes called the High Cascades that run north-south along the west coast of North America from British Columbia through Washington and Oregon to the Shasta Cascade area of northern California. The small part of the range in British Columbia is called the Cascade Mountains or Canadian Cascades; the former term is also sometimes used by Washington residents to refer to the Washington section of the Cascades.
The Cascades are part of the Pacific Ring of Fire, the ring of volcanoes around the Pacific Ocean. All of the known historic eruptions in the contiguous United States have been from Cascade volcanoes. The two most recent were Lassen Peak in 1914 to 1921 and a major eruption of Mount St. Helens in 1980. Minor eruptions of Mount St. Helens have also occurred, most recently in 2005.
The Klamath Mountains
The Klamath Mountains are a mountain range in northwest California and southwest Oregon, the highest peaks being Mount Eddy (2744m / 9002') in Trinity County, California, and Mount Ashland (2296m / 7533') in Jackson County, Oregon. They have a varied geology, with substantial areas of serpentine and marble, and a climate characterised by cold winters with very heavy snowfall, and warm summers with limited rainfall. As a consequence of the geology, they have a unique flora, known as the Klamath-Siskiyou forests, which includes several endemic or near-endemic trees, such as Port Orford-cypress (Chamaecyparis lawsoniana), Foxtail pine (Pinus balfouriana spp, balfourinana), Brewer spruce (Picea breweriana) and Kalmiopsis (Kalmiopsis leachiana), forming one of the largest collections of different conifers in the world. The northernmost range of the Klamath Mountains are known as the Siskiyou Mountains.
The Columbia River Plateau
The Columbia River Plateau lies across parts of the states of Washington, Oregon, and Idaho. During late Miocene and early Pliocene times, one of the largest flood basalts ever to appear on the earth's surface engulfed about 63,000 square miles (160,000 km˛) of the Pacific Northwest, forming a large igneous province. Over a period of perhaps 10 to 15 million years lava flow after lava flow poured out, eventually accumulating to a thickness of more than 6,000 feet (1.8 km). As the molten rock came to the surface, the earth's crust gradually sank into the space left by the rising lava. The subsidence of the crust produced a large, slightly depressed lava plain now known as the Columbia Basin or Plateau. The ancient Columbia River was forced into its present course by the northwesterly advancing lava. The lava, as it flowed over the area, first filled the stream valleys, forming dams that in turn caused impoundments or lakes. In these ancient lake beds are found fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals.
The Basin and Range Region
The Great Basin is a large, arid region of the western United States of America, commonly defined as the contiguous watershed region, roughly between the Rocky Mountains and the Sierra Nevada, that has no natural outlet to the sea. The Great Basin Desert is defined by the extent of characteristic plant species, and covers a somewhat different area. The Great Basin Culture Area, home to the Great Basin tribes also extends further to the north and east than the hydrographic basin.