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The Willamette River (pronounced "wi-LAH-mut") is a tributary of the Columbia, approximately 240 mi (386 km) long, in northwestern Oregon in the United States. Flowing northward between the
Coastal Range and Cascade Range, the river and its tributaries form a basin called the Willamette Valley containing the largest population centers of Oregon, including Portland, which sits along both sides of the river near its mouth on the
Columbia. Its lush valley is fed by prolific rainfall on the western side of the Cascades, forming one of the most fertile
agricultural regions of North America that was the destination for many if not most of the emigrants along the Oregon Trail. The river was an important transportation route throughout much of
the early history of the state, furnishing a means of conveying the vast timber and agricultural resources of the state to the
outside world.
Description
The Willamette rises in three separate forks in the mountains south and southeast of Eugene, at the southern end of the Willamette Valley. The Middle
Fork and North Fork rise on the western side of the Cascades between Three Sisters south to Diamond Peak, with the Middle Fork receiving the North Fork northwest of Oakridge and flowing northwest through the mountains to the southern end of the Willamette Valley.
The Coast Fork rises in the lower mountains
south of Cottage Grove, flowing north to join the
Middle Fork 2 mi (3.2 km) southeast of Eugene.
From Eugene, the combined river flows NNW across the plain of the southern Willamette Valley to Corvallis, then follows a zigzag course past Albany and around the isolated hills in the central valley, passing west of
downtown Salem. From Salem it flows north in a meandering course across the northwest plain of the valley, reaching the hills at Newberg, where it turns sharply ENE along the hills, passing through an
opening in the hills at Oregon City, the location of the
Falls of the Willamette
and the head of navigation. From Oregon City it flows
northwest, past Lake Oswego and Milwaukie on the south edge of Portland, then passing between east and
west Portland, where it is spanned by a series of urban bridges. Northwest of downtown Portland it flows northwest, splitting
into two channels around Sauvie Island, both of which hook around to
enter the Columbia from the west, with the main channel entering on the north edge of Portland and the smaller Multnomah Channel entering
approximately 15 mi (24 km) NNW at St.Helens.
The river's many tributaries drain the surrounding valley and well as portions of the Cascades and the Coastal Range.
Downstream from the confluence of its forks, it is joined by McKenzie
on the north side of Eugene, and by the Long Tom River from the
southwest approximately 10 mi (16 km) south of Corvallis. It is joined by the Calapooia from the southeast 5 mi (8 km) northeast of Corvallis. It is joined by the Santiam from the east and the Luckiamute from the west within 1 mi (1.6 km) of each other approximately 5 mi (8 km) north of Albany. It
is joined by the Yambill from the west at Dayton, by the Molalla from the southeast near Canby, by the
Tualatin from the west at West Linn, and by the Clackamas from the
southeast at Gladstone.
The river forms part of the boundary of the following counties: Benton, Linn, Polk, Marion, Yamhill and
Clackamas. Tributaries of the Willamette River
also drain some or all of Lane, Washington and Multnomah counties.
Although riverboats navigated the
upstream part of the Willamette into the first decades of the 20th century,
currently there is no commercial traffic on the river above the falls. There are public locks to allow boat traffic around the
falls, primarily used for recreational boating.
The river is crossed by serveral ferries along its route in the Willamette Valley.
See also
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